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Bicycles/Maintenance and Repair/Wheels and Tires/Fixing a flat

This page explains how to repair punctures in bicycle inner tubes, and gives some advice as to the most likely causes. In addition, there are notes peculiar to the use of tube sealants.

Terminology
The basic parts of interest are these:

 * Tires are the rubber outer parts
 * that contact the road's surface. The rubber part is called cladding, and it covers the internal structure of the tire.  The cladding has a  tread, smooth or patterned, depending on its use.  The edges that fit into the wheel rims have wires within the cladding called beading or beads, and various fibers run between the beads to give strength within the cladding.  Although tubeless bicycle tires exist, they are still quite rare on pushbikes, so this page deals only with tires having inner-tubes.

 * Inner-tubes are the inflatable parts
 * between the tire and the metal parts of the wheel. They are invisible apart from their valves that protrude through the wheel-rims.  There are three  valve types in use; Schrader valves, Presta valves, and Dunlop valves.  Refer to the adjacent image for examples.

 * Rim-linings protect the bottom of the inner-tube.
 * The ends of the spokes enter the rims, and this lining in the rim-well covers them so that the tube is not damaged.

 * Anti-puncture linings protect the top of the inner-tube.
 * Some high-end tires have protection built-in, but most tires have none. As accessories, they can be easily added between the tire and the inner-tube. They prevent most punctures from thorns, glass, flints, and other sharp objects that contact the running surface of the tire, though they can rub on the tubes and be the cause of punctures in their own right.

 * Self-sealing tubes
 * These are tubes with a clotting fluid inside, (Slime).  They automatically seal punctures as and when they develop.   They can be bought with the fluid in them or for tubes with Schrader valves the fluid can be added separately.

The Causes of Flats
A flat tire or puncture is most often caused by glass, thorns, flints or nails when they cut through the outer rubber tread of the tire and damage the inner tube. These deflations are usually quick, at least when the object is removed. Although this is the most obvious way to get a flat tire there are other ways too. Consider these:

 * Internal abrasion on metal parts
 * If the spoke ends are not covered by the rim-tape properly, then this might happen. Other possibilities include a rubbing valve stem, or a bare edge wire in the rubber parts.  Inspect the inside of the tire for these and for old inclusions that are sometimes missed.   Also, make sure that the valve stem is straight in the rim opening.

 * Rough edges from tube liners or worn internal surfaces in tires
 * Tube liners have been reported to cause punctures, and this author has experienced a slow puncture at the free end of a liner in a two month old tube.  When a tire's cladding is frayed or holed, it can rub on the tube and cause damage.   Tires can sometimes be made good with an internal patch or boot; this is a specially made patch or one improvised by adding a loosely fitted section of old inner tube over the inflated one at the site of the repeated abrasion.

 * Recurrent movement of the tube
 * This happens mostly when tires are soft. The tires flatten or bottom-out on encountering bumps and form double faults or snake-bites in the tire.  Tires inflated to near their maximum have fewest of these.

 * Incorrect seating of the tube
 * If the tube is not seated well before inflating the tire, it is exposed to unusual stresses that lead to single faults called pinches. When inflating tires, first add a little air to the tube then press both sides of the tire around the whole perimeter to check that no tube rubber will be trapped.

 * Rough handling of the tube
 * Some outer tires leak fluid when they are punctured, as do tubes with built-in puncture repair fluids.  These cause the tube to become glued to the inside of the tire.  If the user does not know this and pulls the tube too hard when removing it, a crescent shaped weakness in the rubber results.  These areas usually become punctures, often after only a few days.   Expect binding of slimy tubes when removing them and prize any sticky sections apart carefully.

 * Manufacturing faults
 * These happen sometimes though it is difficult to tell these from other punctures.  If such a fault is obvious then return it for a replacement at the store where it was bought.  Commonly available tubes have a thickness of about 0.9mm though racing tubes are thinner; some downhill tubes are are made up to 2mm thick.  The thicker tubes are slower to produce pinches and snakebites though they have a greater rotational mass, (heavy pedaling), and in any case are rarely stocked by bike shops.

 * A series of recurrent punctures,
 * where there seems to one every other day suggests that either the user is at fault in not properly clearing the cause of punctures, or that a long series of pinches and snakebites are just starting to break through.  Replace the tube, check the state of the inside tire, or perhaps install a tube sealant.

 * Valve leakage
 * Some valve cores can develop slow leaks when the fibers of tube sealants settle within them, and not all valve cores can be removed for cleaning. If a valve is not positioned squarely where it protrudes from the rim of the wheel, then the rubber will be stressed at that point and a puncture is likely to develop.

Replace or Repair?
It is undoubtedly easier to change a tube for a new one than it is to find the puncture in the original. For this reason many riders carry both puncture repair materials and a new tube when they travel for any great distance.

When on the road it is sometimes difficult to find the point on an inner tube that is punctured. If it is a slow puncture it might be possible to pump some air into the tube, perhaps more than once, enough to reach home or a more convenient place to do the work. If is it a quick deflation, then a repair or replacement becomes necessary. When an object penetrates a tire it is best not to remove it immediately if it is the only thing that keeps air in the system. Instead, use the remaining air to get the bike home before removing it.

If the tires are fitted with self-sealing fluids it might be that the puncture will have been fixed already and that the tire just needs to be inflated. A puncturing object should be removed from such a tire only when the part with the inclusion has been rotated to the six-o'clock position; this allows the internal sealant to fully reach the puncture. A different method is needed for slow-to-seal sidewall pinches; allow the fluid to pond at the bottom of the tire then tilt the wheel, slowly rotating it, so that the fluid can reach the internal sidewalls.

If the tire is not self-sealing, and must be repaired rather than replaced, then the remainder of this page will explain how.

The Basic Tools
This section lists the basic requirements for tube repair. The primary items are these:

 * A pump that fits your valves
 * Adaptors too for some pumps.

 * Puncture patches
 * The kind that need glue or the ones that are pre-glued.

 * Rubber vulcanizing solution
 * This is the glue that sticks rubber together. It is not needed for some kinds of patches.  You also need a pin to puncture the top of the tube.

 * A small piece of fine oil paper or sandpaper
 * A pen
 * that can make marks on rubber, like a black Sharpie(TM), or a wax crayon. Users please comment on what is best. I have found that a pen with 'metallic silver' ink works very well for marking inner tubes.

 * Tire levers
 * You need at least two of these; plastic or metal. Some repair kits include these.

 * A talcum block
 * This is included in some puncture kits with a scraper.

Also useful are these:
 * Wrenches
 * If the bike has nutted axles instead of quick-release skewers, you'll need some tools to remove the nuts so you can take the wheel off, e.g. "ring spanner" or some other type of wrench. Some bicycles require two wrenches.  Try out your tools before riding to be sure that they are the right ones to carry.

 * Hex wrenches
 * You might need to release the brakes to get the wheel off.

 * Valve core removal tools
 * These are needed only for tubes with removable valve cores, but are useful when self-sealing fluids have clogged the valves, or the cores have become loose. Removable Presta valve cores such as those of Schwalbe and Bontrager have flats on them that can be turned with pliers.

 * A spare new inner-tube
 * in case all else fails.

The Repair Procedure
Examine the flat tire carefully to find any sharp item that may be responsible. If a nail, thorn, shard of glass, or a flint is found in the outer tire then mark the rubber of the outer tire with a wax crayon or suitable pen so that the location is easily found. Continue to check the tire in case there are more.

Some punctures of inner-tubes also cause damage to the fabric of the outer tire, so look for any potential problems such as a bulge, that suggests a torn carcass, or for exposed carcass cord. If such damage is excessive then it may cause repeated punctures to inner tubes. At this time the method to correct such damage involves the surfacing of the inside of the tire with a so-called boot; a pre-glued patch that keeps the fibers clear of the tube. A piece of an old inner tube can also be used as a temporary fix, if loosely wrapped around the tube in the location of the damage. This latter fix suggests that it might be a good idea to carry an old piece of inner tube in your repair kit. At this time there is no rubber-based filler for cuts in outer tire cladding, so water ingress is likely.

If there is no clear cause of the puncture and the location remains obscure, or if it is a slow puncture, then the wheel will need to be removed to get proper access to the inner tube. Methods are given below that include both wheel removal and repair with the wheel in place.

Bike tire sticks on Rim - solution … It won't always happen but you can't get enough purchase on the edge to push the tire over the inner rim … So what do you do? After several attempts to lever off with the tire lever … The tire and tube were 100% empty of air … I put one foot on VERY FIRMLY on the tire (soft sole) and the applied 1 tire lever to push the bead over the rim and it came over the rim relatively easily.

I was then able to access the tube.

Inserting my spare tube, and making sure it was tucked snugly inside the tire (again completely empty of air), I again had difficulty coaxing the tire bead over the last couple of inches of the wheel rim. (sounds familiar ). by the way leaving the tire on the wheel rim I flipped it inside out and had a good look inside to try (and out ) to try and make sue there were no spikes, pins or thorns on either side that might puncture the new tube.

I had applied all due pressure with both tire levers bring the tire levers closer together but the last few inches was eluding me.

What did I do? You've guessed it. I removed one tire lever and once again I applied my trusty foot to on edge / rim of the tire, and then brought the remaining tire lever along the edge (both hands now available) until I got the tire bead to flip completely over the wheel rim.

Eureka!

Not to be recommended but any port in a storm!

Wheel in place
Most punctures need the wheel removed, but if you are sure that you know where the hole is, you can do the repair with the wheel still on the bike. This method is popular on bikes that need wrenches to remove the wheels, and for rear wheels, even when they are of the quick-release type. However, if the front wheel is of the quick-release type, you will usually find it more comfortable to remove it anyway. The sequence for an on-the-bike repair is just:
 * 1) Prop up the bike in a stable position against a wall, fence, or use the bike stand.
 * 2) Move the punctured part of the wheel to a convenient angle where it is easiest to work.
 * 3) Deflate the tire.
 * 4) Remove one bead of the tire from the rim using tire levers as necessary, then gently pull out the section of tube with the puncture.
 * 5) Correct the problem, then re-inflate the tire.  The methods for doing so are described in the sections below, though readers should ignore the parts that do not apply to their situations.

Wheel Removed

 * Set the bike in an upright position against a wall or fence, and because the bike will become unstable when the wheels are removed, the frame might need to be secured. Some risk scuffing the paintwork and turn the bike upside down for wheel removal.
 * Remove the wheel from the frame. On some bikes, you need to spread or detach the brakes to do this, though deflation of the tire first will usually make it possible.
 * If your bike has Quick release wheels, remove the wheel by loosening and unscrewing the quick-release bolts (skewers).
 * If your wheel is attached to the frame by ordinary nuts, undo them with a ring spanner (wrench).
 * If you have to take off the back wheel, it is usually a bit more complicated, because you need to get the wheel past the chain. If your bike has multiple gears Derailleur gears, change into the very top (smallest) rear and front gears to slacken the chain as much as possible.  This makes it easier to get the wheel off.

Remove the Inner Tube

Be careful too, with the valve when it is removed from its rim, and remember to first remove the locking screw on the rim if the valve is of the Presta type.
 * If the tire is not fully deflated, open the valve and let the rest of the air out, as any residual air will make it difficult to get the tire off and the tube out. If you have Schrader valves then remove the plastic cap and press the center-pin in the middle of the valve.  If you have Presta valves, remove the plastic cap, undo the metal locking screw all the way to its end, then press the end of the valve to release the air.  Later, during patching, the Presta valve can be prevented from refilling again, if necessary, by re-tightening the metal locking screw;  no such procedure is needed for the Schrader since it has an internal spring.
 * With the tire deflated, insert the smooth end of a tire lever under the bead of the tire at a position far from the valve.  While doing this be certain that the inner tube is not trapped by the tire lever.  The tire lever is used with the bent end facing inward so that it can be hooked onto the spoke to keep it positioned.  With it so positioned, insert another tire lever about four inches or so from the first, in the same way.  Continue moving and inserting the tire levers until one bead of the tire is free of the rim.  In the case of wide tires this task is fairly easy but for slim tires another tire lever may be useful.
 * Remove the inner tube very gently, whether it is just a local section or the whole tube. Always anticipate that the tube is sticking to the inside of the tire, and that wrenching it will cause a stretch-weakness.  If the tube seems stuck, then use extra care in separating it from the tire, perhaps softening any glued-up tube sealant with some water before easing the two apart.

Find the Puncture

 * If you intend repairing the tube without removing the wheel, the location of the puncture will be already known, but otherwise the puncture still needs found.
 * Remove any penetrating objects, and carefully inspect the inside of the tire, visually and by hand contact to make sure that there are no remaining causes of punctures.
 * A fast leak in the tube can be found by inflating the tube and listening for the escaping air. Another method is to dampen a hand, then detect the cooling effect of the leak by feeling around the tube.  Sometimes a small hole is visible, especially near a stretch mark on the tube, or in a place that was sticking to the inside of the tire.   Another likely place is at the free end of a  tire liner.  If the leak is still not found then submerge the inflated tube in a basin or a sink to look for air bubbles.  During this process, it helps if the tube is folded and compressed with the hands to aggravate the leak.  Use a ball point pen, felt marker, or the chalk supplied with your puncture repair kit to mark an X on the location of the puncture. Make the X somewhat wider than the patch diameter. This will enable you to center the patch over the hole.

Repair the Tube

 * In the area of the puncture, lightly roughen the surface of the tube with the sandpaper to expose clean rubber for the bonding process. Rubber-to-rubber patches make continuous bonds that extend though the glue layer. Although the stresses on tube patches are fairly low, there are nonetheless optimal conditions for success:
 * Surfaces must be clean, dry, flat, and oil-free.
 * This assures a good connection.

 * The glue layer must be thin.
 * Thin layers are strong and airtight and bonding is fast.

 * The bonding must be undisturbed.
 * Escaping air or movement will weaken it.

 * The best patches are pressed while they set.
 * Press the parts together.

 * Make sure that the tube is completely deflated before applying a patch as escaping air might spoil the effort; Presta valves can be locked if need be, to prevent their re-filling. There are different kinds of patches in use, and each kind is accompanied by instructions of its own. A few of these are mentioned below.
 * Pre-glued rubber patches with foil backings usually require that a thin film of glue be applied to the tube, slightly larger than the intended patch, and left until tacky. Then the backing is removed and the patch is stuck firmly onto the puncture. To avoid handling the glued surface, expose one corner of the patch first and apply it to the tube, then withdraw the remainder of the backing while completing the connection.  Some have a handling film that can be left in place.   If too much glue has been used, be sure to press the parts together for an extended period before use; hours rather than minutes.
 * Recently, thin clear-film patches have been made available. These do not need a priming layer of glue, and are pre-glued. After surface preparation, these are transferred to the tube directly, using the progressive removal of the backing as described above. Like other methods, they depend on a clean, dry, oil-free, flat surface for the greatest success.  They are perhaps the easiest to use, and do not need a separate glue supply.
 * Conventional rubber patches need a thin priming layer for the tube and also for the patch, then when tacky, the patch is made.
 * After making the patch scrape some of the talcum block onto any visible glue to prevent sticking.
 * The bond of the patch strengthens with time. Although a perfect patch can be used almost immediately, if there is no real hurry, leave the patch to set as long as possible before inflation.
 * The most difficult patch to make is one located near a ridge in the rubber; the ridge spoils the airtight connection, and ridges are hard to remove or make flat enough, even with sandpaper. Sealant-filled tubes can repair such punctures without difficulty.

Refit the Tube

 * Before the replacement of the inner tube, make sure that the causes of the puncture have been removed.  In addition, run fingers around the inside of the tire to find any rough spots that could cause damage to the tube; if found, they can be fitted with a boot, a durable seal that goes over the rough bits of the inner tire, or a loose piece of old inner tube around that section of the tube itself.  Check that the rim tape, (liner), covers the spoke ends and clean any leaked  sealant from the inner tire with a damp cloth.
 * Some tires have arrows on the sidewalls to indicate which way round the tire tread is to be aligned; make sure that this is correct. When all is well, add a little air to the tube to give it some shape, and fit it into the tire. Take care in feeding the valve stem through the rim cutout.
 * Starting at the section with the valve, work around the wheel, pushing one bead of the tire onto the rim, using your hands only. If you use a tire lever it is difficult to avoid trapping the tube between the rim and the tire. Make sure also that the valve is straight at the end of this stage, and if it is not then gently straighten it by shifting the tube's position on the rim; not by pulling on the valve.
 * Repeat the process to set the second bead of the tire onto the rim following the same procedure as for the first.  Re-check the straightness of the valve stem and make any corrections before proceeding beyond this stage.
 * Work around the tire, pressing both sides toward the center of the rim. If this is easily done then it is clear that the tube is not trapped at any point.
 * Inflate the tire and install it on the bike, paying attention to the inflation limits marked on the tire's sidewall.

Valve Problems
Any inner tube can be checked for leaks by first inflating it, and submerging it in water. Telltale air bubbles will seen emerging from the site of the leak. This process can be made more effective by forcing sections of the tire between the hands to increase the leakage.

A slow leak can sometimes be caused by the valve itself. Sometimes a leak can be seen in a valve by wetting its various parts with a soapy solution and looking for bubbles.

To try to fix a leaking Schrader valve, deflate the tire, unscrew the valve body with a keyed valve cap or valve tool, and examine the seat or rubber sealing ring for cuts or nicks, dust, lint, or fibers that prevent the valve from closing fully. Likewise check the valve seat and the bore of the valve stem. Clean if necessary. The valve body may be replaced. If no spares exist, an emergency fix can be had by inflating the tire with the valve sealed with silicon rubber, caulk, or cured epoxy resin. Obviously the tube must be discarded after such a process.

If the Presta valves cannot be disassembled, then tubes with leaking valves must be replaced. Some Presta valves, for example, those made by Schwalbe and those of Bontrager have removable cores, but most do not. Such valves can be recognized since they have flat sections on them to allow slackening and tightening of the cores with a valve removal tool.

Internal tube sealants can block both valve stems and cores. However, stems are easily cleared with a thin object after the cores are removed, and sealant can be removed from the cores by washing them in water.

Self Sealing Tires
Sealants will seal most small punctures in tires up to about one eighth of an inch in size. The product (Slime), is already in some tubes bought from bike shops, but can be poured into existing tubes, provided that they have removable valve cores. There are a few points peculiar to the use of tires with internal sealants.
 * New tires with sealant
 * When a tube with sealant is first installed, rotate the wheel quickly several times, occasionally operating the brake, to fully spread the product.

 * Parking position for the wheels
 * Because valves might become clogged with sealant when the bike is stationary for any length of time, the wheels should be routinely set to a position that allows the solution to drain from the valve. The position that does this best is either the five o'clock or seven o'clock positions.  See the adjacent diagram.

 * Inflating sealed tires
 * When the tires are being inflated there is a significant airflow.  To avoid any unnecessary clotting of the sealant, position the valves as for parking, in the five o'clock or seven o'clock positions.

 * Clogged valves
 * Despite best efforts, and sometimes at the point of purchase, the valve core or the valve stem will be blocked.  For this reason it is always best to use tubes with removable cores; these can be rinsed in water to clean them, or the stems can be unblocked with a thin object.   A valve removal tool is useful.

 * Removing puncturing objects
 * Before removing a penetrating object from a sealed tire, first rotate the site of the puncture to the six-o'clock position to give maximum exposure to the sealant pool.  This will minimize the air loss before the puncture is sealed.

 * Slow puncture repair
 * Sidewall punctures, snakebites and pinches are sometimes slow to heal.  This is because the airflow is low and the conventional rotation speed might be excessive.   To make sure that slow punctures are fixed, first allow the sealant to pool at the bottom of the tire, then tilt the wheel and slowly rotate it so that the sidewall has full access to the sealant.   Repeat for the other sidewall.

 * Patching a sealed tube
 * Sealant leaked into a tire can be removed with a wet cloth. Punctures too big for the sealant to handle can be patched in the usual way, but the patch will fail unless all traces of sealant are first removed from the surface. During the sealing of punctures, a small amount of sealant can cause sticking of the tube to the inside of the tire.  When such tubes are being removed, try to anticipate this so that the tube is not weakened by the inevitable stretching.  Rather than tugging the tube, consider using water to soften the gluing effect.


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Bicycles/Maintenance and Repair/Wheels and Tires/Truing a bicycle wheel

Overview
A bicycle wheel consists of a central hub and a round rim, joined by a number of spokes. Spokes radiate from the hub to the rim, where they are anchored in a screw-thread attachment called a nipple. By tightening and loosening the nipples, it is possible to bring the wheel back into round (vertical true) or remove a side to side wobble (lateral true).

Spokes may be arranged in a variety of patterns, of which three-cross, four-cross and radial are the most common. The pattern affects the strength, weight and characteristics of the wheel but is not particularly relevant to the process of truing.

Tools Needed
To build or to maintain a spoked wheel, a spoke wrench is necessary. The flat-to-flat dimensions of a typical spoke nipple are too small to fit any commonly-available open-end wrench. Any good bicycle shop will, however, stock a selection of spoke wrenches, with price and quality being proportional.

A spoke 'twiddler', or nipple driver, is a tool that may be useful in the course of assembling a new wheel from its component parts - hub, spokes, and rim. It isn't necessary - especially if you aren't building a wheel - but it can save some time. Similar to a screwdriver, but with an off-set blade that rotates freely in the handle, it is used on the slotted outer face of the nipple - which resembles a slotted screw. A spoke 'twiddler' allows for rapid assembly of the wheel - or installation of a nipple on a single spoke - and is designed to self-limit the extent to which a nipple can be threaded onto a spoke.

A spoke wrench is used to bring tension to the spokes, and is applied to the square part of the nipple that protrudes inward at the rim. Unlike the 'twiddler', the spoke wrench is designed to turn the nipple when the spoke is under tension. This difference is what makes the spoke wrench essential.

A truing stand is a purpose-built stand into which a wheel (rim, spokes, and hub, with axle) is installed during wheel-building, wheel repair, or wheel maintenance. A truing stand is very useful - possibly essential - for making hand-built wheels. Effectively, it is a rugged, precision-made jig for holding the axle of the wheel solidly in place. By extension, the rim thus has a steady reference in the axle in the hub held in the truing stand. The rim is, therefore, also found in relation to a caliper, or set of calipers, built into the truing stand, and against which checks are made for radial and lateral true (read 'perfection') during the course of building or adjusting a wheel. For extreme accuracy in measuring true, an optional dial indicator may be fitted to the truing stand, and a separate tensiometer may be kept to hand to test for proper tension on all the spokes (tension-balancing). Instructions for creating an inexpensive, but very accurate, truing stand are here.

A dishing tool is used to measure the extent to which the axle juts out past the rim. Since a true wheel has the plane of the rim centered laterally between the points on the axle at which the axle is fixed to the frame, the offset of the rim from that anchor point on one side of the wheel should be identical to the corresponding offset on the other side. A dishing tool is used as a comparator: the offset on one side is measured using the tool, that setting is 'stored' in the tool, and the tool is applied to the other side of the wheel for purposes of comparison; the deviation of the second side's offset from that of the first's indicates the direction in which, and the extent to which, the rim needs to be moved to make the wheel true. However, a dishing tool is not strictly necessary if you have a good truing stand: if it's understood that a true wheel (abstracting from the particularities of the hub and the spokes) is symmetrical (i.e. the rim itself is, in some sense, 'centered' on the axle) then you can use the truing stand's caliper (or calipers). and an occasional flipping of the wheel in the stand, to serve the same function as a dishing tool.

Tools, Punting
In most cases, especially when truing as maintenance on a wheel that has already been built, checking the tension on the spokes by ensuring that they all make the same tone when "pinged" with a fingernail will work fine. Checking the dish is also unnecessary on minor repairs, as most good truing stands will be able to give an accurate idea of how close the wheel is to centered, though it is probably a good idea to take the wheel out and re-settle it in the stand to double check. It's necessary to measure the distance if you are truing a wheel that is meant to have an offset, but this is very rare.

In a situation where a stand is not available, the brake calipers on a bicycle can be used to measure true while the wheel is still attached, but this is less than ideal. Also, if no other option is available, a small adjustable wrench can be used instead of a spoke wrench or key, but extra care should be taken not to strip the nipples. A glass cutter made by Richards has one opening small enough that it can be enlarged slightly to make a passable 0 spoke wrench - or a 1 or 2, if that's what you need.

If a rim has been 'pringled', or 'potato-chipped', into a saddle shape, by a lateral blow, it will be difficult to straighten by spoke tensioning alone - in fact, it is probably impossible to overcome severe rim warping this way. Often, however, it is possible to restore the wheel to a nearly-true state, even if it seems hopelessly warped. The procedure that follows should be applied as soon as possible after the trauma; leaving the wheel in it warped state for more than a few days will likely cause the wheel to cold-set - meaning it will retain the new shape in which it is left, and probably will have to be replaced.

In order to effect the following quickie repair, you must have a properly inflated tube and tire still on the rim, and the rim itself should only be generally out of shape, with no damage to the rim wall itself. To wit: standing with your feet shoulder-width apart, with both hands, grip the wheel firmly by the rim and rubber at the point directly opposite the point on the circumference that is most obviously bent away from the principle plane of the wheel; bend slightly at the waist and position the point of the tire opposite on the ground in front of you, with the wheel at an angle of 45 degrees to the ground (possibly greater, depending on the denomination of the tire), and the bent part heading earthward; raise that point off the ground a few inches and let it fall again, ensuring that in the next step, only the tire - and no part of the rim - is going to strike the ground; without straightening at the waist, or bending over further, raise the wheel off the ground to about head or chest height, then forcibly bring the wheel down in such a way as to strike the ground sharply with the inflated tube and tire at the point opposite your grip; the rim should pop back to very nearly true. You can't undo damage done by striking the rim on the ground, so plan carefully, and rehearse mentally before committing to this repair.

If the quickie fix above has improved matters, it's usually possible to improve the situation further with the usual techniques required of truing or maintaining a wheel.

In the event that the above procedure doesn't bring the rim back to at least a rideable state, it may be necessary to replace the rim or the entire wheel. Note, though, that a rim can often be straightened, at least to some extent, by placing the rim (with appropriately loosened spokes) between two rigid objects (e.g. a pair of closely-spaced pipes, or between a door and its cross-wise bar-like handle) and, using a prying action, creeping up on the desired degree of 'flat'. Don't bend the rim more than necessary, work iteratively, check frequently on your progress, and be aware that you may need to overshoot your target slightly to allow for the tendency of metals to spring back from bending.

It should be noted that repairing local rim damage with pliers or even a hammer and anvil is never advised - because less dramatic, more effective, methods are available which will not cause even superficial damage to the rim wall - the all-important braking surface in most cases. Instead of pliers neat, repair a flairing of the rim by sandwiching the rim between two thin, very flat pieces of metal (e.g. two cone wrenches) and placing this in the jaws of channel-lock pliers. An alternative method for repairing rim flairing is to use blocks of wood as both anvil - below the rim - and hammer - above the rim. If it seems necessary to use a hammer, don't strike the rim directly with the hammer's face; lay a strip of aluminum or brass over the area of the rim to be repaired, and strike there. Aluminum cans - ubiquitous and easily cut with scissors or even a pocket knife - are indispensable in bicycle repair.

Truing the Wheel
First, remove the wheel from the bike and remove the tire and tube before placing it in the truing stand. Adjust the arm and caliper on the stand so that the caliper is just shy of touching both sides of the wheel. Now, spin the wheel and slowly close the stand's calipers until they scrape against a spot on the wheel.

Once you've found a spot where you are out of lateral true, tighten the spoke or spokes on the side opposite the bump, and loosen the ones that are pulling it out of true. Be patient while doing this - you shouldn't be going more than a quarter turn at a time while truing like this. If the spokes are giving resistance, try over turning slightly, and turning back to where you intended.

After you've gone through several passes like this, you should check the vertical true of the wheel to make sure that you haven't put it out of round. Re-adjust the arm and caliper of the stand so that the calipers are together and just underneath the rim. Spin the wheel, and this time adjust the arm until the wheel begins to scrape.

While adjusting for vertical true, you should tighten the spoke at the center of the hump, and tighten the spokes to the sides one half as much each. Because these spokes will be on opposite sides of the wheel, this will ensure that you don't put the wheel very much out of lateral true. If the hump is between two spokes, tighten them equally. Adjusting the spokes in one place will affect another section of the wheel, somewhat like squeezing a balloon.

After this is done, you should check for lateral true and even tension, retruing for both lateral and vertical true if the wheel is out.

If the wheel is properly trued and tensioned, you should stress test the wheel by placing it on one side and pressing down on it fairly firmly. You should repeat this going around the wheel, in order to be sure that the spokes settle into position with the spokes that they cross now and not while the wheel is being ridden. This can also put the wheel out of true again, and this should be checked.

A full, comprehensive discussion of bicycle wheel building and truing is found in Jobst Brandt's book The Bicycle Wheel ISBN 0960723668.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Bicycles/Maintenance and Repair/Brakes/Adjusting Rim Brakes

ADJUSTING RIM BRAKES Rim brakes on bicycles are simple to adjust, and the term rim is used to distinguish them from hub brakes. Rim brakes include all brake designs that depend on using brake pads to close on the rims of a bicycle's wheels. The brake parts for the most common configuration are identified in Figures 1 and 2.

Although brakes are usually mandatory on bicycles, the laws and rules for brake performance vary, and some countries, while making law for new bicycles, ('at the point of sale'), have few specifications for the operation of bicycles after that point. Bike riders are advised to use the sources of law that apply in their own countries, but where the rules there are incomplete or unclear, they are advised to use any point of sale specifications that are available. Because the matter might then still be unclear in some countries, a table below repeats the braking distances of British Standard BS6102/1 for new bicycles.

Bike shops can perform any number of tasks for the bicycle owner, but the basic brake adjustments are easy to do for yourself. At the simplest level they consist of screw adjustments on the handlebars, while knowing what gaps you intend to produce. At other times, (rarely), the cable length needs to be changed, but this too can be done by anybody with a practical leaning. It is perhaps when the conventional adjustments fail to solve the problem that most people resort to such pages to learn more. This page includes a selection of the most common confusions for brake adjustment and explains how to correct them.

Bear in mind that the best way to learn the adjustment of brakes is to be shown by somebody while it is being done; in this way much of the mystery vanishes. The next best way is to follow a fairly stolid description of the sort below, and although it lacks interaction, should at least leave the reader better informed than when he started.

Preliminaries
Consider these few things before carrying out brake adjustments. Doing so might save time in the long run:

 * Is a full adjustment really needed? Before doing any elaborate brake adjustments it is a good idea to decide whether or not a simple barrel adjustment might fix it. If you just need a slight gap adjustment or to balance the brake arms refer to  Fine Adjustments below.

 * Make sure that the wheels are correctly set.  The wheels should be fully engaged in the dropouts and centered in the wheel arches if brake balancing is to work.  If they are not centered, then this might be your problem as opposed to the brakes themselves; so correct the matter first.

 * Inflate the tires first. Before adjusting the brakes, make sure that the tires are properly inflated, since flat tires will affect the results. Metal rims can move as tire pressures change.

 * Preset the barrel adjusters. Before starting any cable length adjustments, first set the brake levers' barrel adjusters so that they are out by two full turns, instead of being tightened all the way in.  This allows some fine adjustment in both directions at any stage, and will allow the cable to be slackened enough to release the wheel from the brake blocks when necessary.

 * Check that the rims are clean. Remove any dirt and oil from the rims, and if necessary clean them with detergent and wire wool, being careful to avoid the rubber of the tires.

 * Check the brake blocks for wear.  Make sure that the brake block contact areas have not been badly reduced.   If the surface grooves on the blocks have been removed by wear, then replacing them will improve braking greatly.   When replacing them be sure to replace both at the same time.

The Full Procedure

The full adjustment procedure is summarized below but it should be emphasized that slight adjustments might solve the problem. In any case, it is quite usual to repeat balancing at various stages throughout the adjustment.

 * Position each brake block so that it presses cleanly onto its wheel rim.

 * Set the brake cable length to roughly establish the brake blocks' clearance.

 * Adjust the brake-arm balance screws so that both blocks close onto the rims together.

 * Fine-adjust the handlebar barrel-adjuster for the required brake performance.

 * Test the brakes both off and on the road.

These above points are all described in some detail in the text that follows.

Brake Block Alignment
The brake blocks need to be aligned with the metal rims. Refer to Figs 1 and 3. The leading edge of each block should be slightly closer to the rim than its trailing edge. This prevents brake squealing and is called "toeing-in". Use a coin, a credit card, or any other thin material under the back end of the block while adjusting it. Some suggest tying an elastic band temporarily to the trailing end of the block to allow more freedom while working.

To make the adjustment, slacken the screw that holds the block. Usually a 5mm hex wrench is used. Swing the brake arm in so that the block is pressed squarely against the metal rim, and then re-tighten it while holding the block hard with your "toeing-in" device in place. Avoid the rubber of the wheel; the block should contact only the rim. The block should be parallel to the rim, noting that some blocks are curved to fit its shape. Do one block at a time, and just let each arm relax after the block is set. If there is insufficient clearance to work or if you intend adjusting the cable length later in any case, then unhook the cable bridge (Figure 1, D) or undo the cable clamp (Figure 1, F) before carrying out the work.

Block Clearance
Decide whether or not the block clearance is correct by trying the feel of the brake lever. (Figure 2, D). The brake should feel responsive without too much handbrake slack prior to the start of braking. Some mountain bike V-brakes might need only a 1mm gap, while many other brakes need about 2mm. If in doubt, refer to your bicycle handbook. If a significant adjustment is needed, resetting the cable length should do it. If a small change will do then use the brake lever barrel-adjusters on the handlebars, as described in the Fine Adjustments   below.

Rough Adjustment

 * To reset the cable length slacken the brake cable clamp (Figure 1, F), usually with a 5mm hex wrench, and let the brake side arms relax.     Move both of the side arms toward the rims until the blocks are about the right distance away; although you can do this in any way that you like, it is easiest to hold one arm against its rim and adjust the other's gap so that it is about double the intended block clearance.   Pull up any cable slack and re-tighten the cable clamp.  This may take a couple of tries to get the blocks close to, but not touching, the rim.   In any case, fine adjustments can be made with the barrel adjusters (Figure 2, B), provided not too much range is expected of them.

Alternatively, to set cable tension, back the barrel adjusters off a few extra turns, squeeze both pads against the rim, tighten the cable pinch bolt, then back of the barrel adjuster until the wheel spins freely between the pads.

 * In the absence of documentation about the brakes, aim for the combined clearance of the two blocks on v-brakes to be about 2mm; this will give 1mm gaps after balancing.  For less demanding brakes, assume about double this figure.   Some manufacturers provide internet sites with technical information of this kind.   A good example of a manufacturer's brake manual can be found in pdf format here, and its parts list  here.

Fine Adjustment

 * Fine adjustments are made with the handbrakes' barrel-adjusters. (Figure 2, B).  If not on the handlebars they may be near the brake blocks.   If the brakes just need a small adjustment, this may be all that you need.

 * Barrel adjustment; after undoing the barrel-adjuster's locknut (Figure 2, C) the brake blocks can be moved by turning the barrel screw (Figure 2, B).   To move both brake blocks inward, simply unscrew the barrel (counter clockwise).  Conversely, to move both brake blocks outward, turn the barrel inward, (clockwise).   This feature gives a much finer adjustment of cable length than setting the cable clamp.   Check the feeling of the brake frequently while getting the adjustment right, and tighten the locknut again when it is done.  Lastly, decide whether or not to re-balance the brake arms.

 * Notes on barrel range:  There are differences of opinion as to the ideal amount of thread to leave on the adjusters when the brake adjustments are complete.   The main ideas are these:
 * For maximum barrel range; screw the barrel adjusters all the way in before making any brake adjustments to allow the widest range of inward adjustment of the blocks.  This might be the case where compensating for block wear is the main consideration.
 * To unhook the brakes; for a wide wheel removal, you might wish that you left more play in the cable.  That is to say, provided that the barrel has always about two turns of thread showing, then tightening it all the way in will allow the cable nipple, (the end of the cable guide), to be unhooked from the housing detent without touching the cable clamp.  Some find this method useful. Decide which is best for your routine.

Brake Block Balance
'The brake arms should be adjusted so that both blocks apply pressure to the rim at the same time. As a result, at balance, there is no sideways displacement of the wheel during braking. Although slight imbalance is not always critical, displacement of the wheel by even a small amount can cause damage when small-clearance devices such as distance counters are installed on the spokes. Balancing the spring tensions keeps the wheel centered even during braking.

For brakes like V-brakes, there is a small screw near the bottom of each brake arm to adjust the spring tension.( Fig 5). It is often a  posidrive screw, (M4x6mm), with a tightening insert. Turning this screw clockwise will cause the brake block to move outward slightly, and turning it counterclockwise will cause the block to move inward. As one block moves, so does the other, to maintain the distance between them. Adjust these until the clearances are about equal. In this way, operating the brake causes the blocks to reach the rim at about the same time.

Be careful not to withdraw the screws too far since they may not be captive. At the other extreme, if a screw is too far in, the brake arm will bind; if a brake arm seems inactive, or unresponsive, this might be the case, or the spring may just have popped out of its slot. Try to avoid the limits and to reach a balance with the screws near their mid-range. This is easier than it sounds since making an identical adjustment on both screws will leave the balance unchanged. Brakes usually can be balanced unless the wheel is not centered in the wheel-arch. (See Common Brake Problems on this page for more on this).

Final Check
Test the brakes on the spinning wheels before riding. If these work well enough then test the brakes again by riding the bicycle in a quiet place. The brakes should stop the bicycle decisively in a fairly short distance. Some v-brakes in particular have a short stopping distance; on these you should not need a deep pull on the brake lever for a good braking effect since this is a sign that the blocks are set too far from the rims. In any case be sure to refer to the manual if there is doubt.

Figure 4 is an extract of maximum braking distances as given by the CTC Hire Standard, that is itself related to the content of British Standard BS6102/1 for new bikes. The CTC standard is an attempt to consider used bikes, as opposed to bikes at the point of first sale. In any case, these stopping distances are useful until such time as the European standards properly address the issue.

The most common reason for long braking distances, apart from maladjusted brakes, is the degradation of the brake block surface area. Be sure if replacing these to replace both together.

Balance Problems
Sometimes, despite best efforts, the brake arms will not balance. The spring balance screws are designed to have limited range since they are only expected to handle the difference between the arm tensions to achieve balance. So, faults that only slightly bind any part of the braking system can cause trouble with balancing. Possible faults include:  The lack of general lubrication, the binding of brake arms, the slipping of faulty adjustment screws, unseated brake-arm springs, unseated housing ferrules or nipples, or a quick-release wheel that needs re-clamped closer to the  centre of the wheel arch. See these points below.
 * Lubrication
 * Small changes in brake arm resistance are often corrected by lubrication alone.  As a last resort, to identify the source of binding, undo the cables at the brake levers, and at the cable clamp; this can isolate the three parts of the system.   In this way, each section could be studied without being affected by the other parts.   Any roughness in operation could  then be observed.   Many problems of this kind however, are solved by routine cable lubrication.

 * The moving parts of brake assemblies, with the exception of blocks and rims, should be oiled.  Use a light machine oil of the type sold as 'bicycle oil'.   Brake lever assemblies, cables, and the brake arms should all be lubricated.   A cable is oiled by dropping oil onto the cable with the brake lever operated to expose it.   A single drop of oil at the point where a cable enters a housing will travel the length of the cable by capillary action. Rub some oil also onto any other visible steel cables.   When the brake arms are removed, do not forget to clean and grease the  mounting pins before reassembly.   The rotating parts at the back of the brake arm's pivot-assembly should not be disassembled, though a drop of bike oil is useful when they seem a bit gritty in operation.

 * Balance Screws
 * The balance screws work by pushing and releasing the coiled ends of the springs, so increasing and decreasing their strength. However, things sometimes go wrong.

 * In some brakes the brake arm binds up when the screw is all the way in.   In others, the screw slips off the end of its spring because of bent parts or poor design.   When either of these things happens it will be difficult or impossible to balance the brakes.

 * If the balance screws seem to lack range of adjustment. then look for these problems on the underside of the brake arms.  In the case of binding screws it is simple to release the screw a bit and reattempt the balance.  Bear in mind that carrying out an identical adjustment on both balance screws should leave the balance unchanged, so unless there is some other problem, it will usually be possible to correct binding in this way. A better fix for a binding screw is to add a washer under the balance screw head to avoid binding in the future.   This limit should be set to avoid the worst case; found usually with the block against the rim. If the screws are ever replaced, avoid using screws that are longer, unless the extra is padded out as mentioned above.   This will avoid brake binding.   Balance screws are usually fitted with nylon inserts to make sure that they are fairly tight, though a drop of thread tightening fluid might also help avoid their getting lost on the road.

 * Sometimes the spring on a brake arm slips out of its groove, and this is seen as one side of the brakes doing nothing at all.  This happens at times when the bridge has been undone.   Fix it by moving the spring back behind the arm into its groove.   At other times, the springs of cheaper brakes can slip off the balance screws, but this is largely a fabrication problem; consider a new set of brakes if this happens, since these springs are not easily reworked.

 * Brake arms have location pins to fix them to the flats on the bike frame.  The frame often has three holes to choose from but some frame mountings have only one.   The hole chosen decides the spring strength and the work needed to pull the brake lever.   If the pins of each brake arm in a set are located in different positions, then the resulting tensions cannot be balanced.   If there is an obvious imbalance in the brake arms and the arms were recently reinstalled, then consider this possibility.   Although some frames are provided with three holes for the location pins, some brakes only work on one particular position, so take note during any disassembly as to which holes were used.

 * Obstructed Cables and Housings
 * It has been noted that accessories such as straps, lock cables, and bungee cords are easily forgotten, and can bear upon brake cables in such a way as to make the balance seem impossible.  The same condition is possible when the parts at the ends of cable housings (ferrules), become unseated during brake work; the entire brake balance suffers.   Baggage on the front handlebars can kink cable housings, and a similar binding can be found in folding bicycles; in the latter case, when the bike is unfolded, make sure that any tight loops near the hinge points are straightened before making off.  If the change is fairly sudden, and in particular after parking the bike or unhooking the cable bridge, then look for these simple solutions.

 * Wheel not Centered
 * Many brake balance problems are associated with wheel positioning.  There are at least three situations to consider:
 * When a quick-release wheel is positioned within the wheel arch it can happen that it is not fully engaged in the dropouts.  This happens when a wheel is installed with the bike in a stand or otherwise above ground.   A gap is often visible.   This problem causes the brake blocks to close on the rubber of the wheels instead of the rims, so it is not subtle.   Reset the wheel.
 * Brakes are adjusted for the quick release lever positioned on the left of the bike.  When a front wheel is wrongly installed with the clamp on the right, the existing brake balance will be upset.   Reinstall the wheel with the lever on the left.
 * When a wheel's skewer-clamp is tightened it is important to hold the wheel in a correctly centered position during the process. Bad centering can also cause the bike to run poorly, might feel a bit heavy, and can make shifts a bit less certain. The two springs, one on each end of the skewer, (both with their pointed ends inwards) are there to help the skewer start off in the center.  The springs are not strictly necessary for the skewer to work, and as such they might be missing.  In any case a wheel can be centered by adjusting both the lever and the locknut. One way to do this is to slacken both ends until the exposed screw threads look about equal, then tighten both the locknut and the lever a little bit at a time.   Make final adjustments in the same way until resistance is first noted when the closing of the lever approaches the horizontal.   Some tires have a center ridge that is  useful for checking that the wheel is centered.   When this problem is corrected the brake balancing adjustments will come into range, and the bike might even run better.

 * Brake Arm Spacers
 * Each brake arm has a brake block and on its screw thread there are various washers and spacers.  One of these spacers is wider than the other, and they can be interchanged, in order to get the brake arm spacing within range for effective balancing.   If the brake blocks (pads) were recently changed or removed, check that there is symmetry in their choice.   If one pad has the wide washer near to the pad and the other has the narrow one then the distance of each brake block to the rim will be different and they will not balance.   The Tektro brake manufacturer has a pdf file that explains how to decide which spacer to use for their products, though it has been found to have some generality.

 * Badly Worn Brake Blocks
 * If one brake block has been worn down much more than the other then that might affect whether or not the brakes balance, especially if it is combined with some other trivial factor.  Inspect the blocks and if changing them be sure to change both at the same time.    Generally speaking, if a brake block has been worn down so that any part of any of any of its grooves is no longer clear then they both need replaced.

 * All Else Fails
 * If the brakes balance, but at opposite screw extremes, then further adjustments are prevented. First consider all of the above solutions; i.e., is the tighter of the two binding, etc.?   If you are stuck with unmatched springs in the brake arms, (rare, since the set that came with the bike are matched in manufacture), it may be possible to get the screws back into mid-range with a washer or two.    Add thin 6mm washers, as shown in Figure 6, to the brake block assembly that habitually has the wider of the two gaps.   Adjust the number of washers until the balance is achieved closer to the balance screws' midpoints.   When all else has failed, and a fix of this kind is being considered, do not forget to consider the buying of a new set of brakes, and getting the bike shop to first take a look.

Soft Brakes
If brakes are softer than intended, even after adjustment, then it might be that the toeing-in is excessive. Also, if wheel wobble causes rubbing on the brake blocks, widening the gaps will necessarily soften the brakes. See the comments below.

 * Excessive Toeing-in
 * It is impossible to set firm brakes if the blocks cannot be set close to the rims.  For brakes needing narrow' clearances, e.g. 1mm to 1.5mm, the toeing-in needs also to be narrower than usual.   If the toeing-in were set to the usual 1mm more than the front of the block, then for the above example, the average clearance for each block would be 1.5mm to 2mm, and the brake would feel soft.   Thus, the toeing-in needs to be minimal if a firm or hard brake is required.   In fact some brake manufacturers recommend no toeing-in for their products.   Brakes that use wider settings by design, are affected  less by toeing-in.

 * Wheel Wobble
 * Wheel wobble causes repetitive brake noise but most brake noises are unimportant.  The most common cause is debris from the road.   Also, new tires have rubber tails on them that rub on brake blocks, but these can be trimmed.   Badly centered wheels can  also cause some rubbing of the brakes.   It is as well to check this if the problem follows recent wheel work.   These noises are not serious.

 * If there is even a slight wheel wobble then brake block clearances will need to be widened to avoid the repetitive rubbing noise.  Although some wheel wobble is inevitable, when it is excessive then repairs may be required.   In that case see:  Truing a bicycle wheel, in an attempt to handle it yourself, or consider getting some advice from your bike shop.

 * For brakes that need narrow clearances, say 1mm, the issue of wheel balance is more critical.  Widening the block clearances to 2mm, to accommodate a slight wobble makes softer brakes, but in most cases these will still be safe.   However, if the wobble worsens, then continuing to widen the clearances will lead to ineffective brakes long before the wheel itself becomes unusable.   Brakes designed for wider clearances will accommodate more wobble before the brakes suffer.

Cables and Housings
The subject has been given a separate page at Cables and Housings.


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Bicycles/Maintenance and Repair/Chains/Mending a broken chain

Mending a broken chain
Newer, narrower chains and wider chains for single speed or three speed bicycles often have special links for removing the chain, but the chain tool is still needed to remove excess links when replacing chains.

A chain tool can be used to push out the rivet which joins the plates of the chain together. Many chain tools have two positions the chain will fit- make sure the plate furthest from the extractor pin is supported by the tool. Once this is done the chain can be replaced or re-assembled as a shorter chain. Most chains will have enough slack to allow removal of a few links without making the chain too short.

Avoid pushing the rivet all the way out, it should remain lodged in one of the outer plates. A small portion of the rivet left protruding on the inside of the plate can hold the chain together during reinstallation. Use the same position in the chain tool, with the chain plate furthest from the chain tool's pin supported, and push the rivet back into place. After reinstallation, the link will usually be too stiff- leading to chain skip unless loosened. The other position in two-position chain tools, with the closer plate supported by the tool, is used for loosening tight links. Force the side of the rivet that protrudes more into the link to loosen the link. Alternatively, grasping the chain on both sides of the tight link and flexing the chain in and out will loosen the link.

Note
Although they're made of metal, chains seem to "stretch" as the links wear. This will cause them to not engage on the gears properly (they will hook on to the middle or top of the tooth, instead of the bottom of the groove). This will also cause the gear teeth to wear down.

To test for excessive wear on a chain, open a link and remove the chain. Then try to flex the chain sideways, in the direction it is not supposed to bend. If you can make anything more than a 1/8 arc (for example, if you can make a half circle or if you can touch the ends), then your chain is worn and should be replaced. Alternatively, measure a straight section of chain under slight tension. Standard links of chain measure one inch when new- if 11 links of chain measure 11 1/8" (283 mm) or more the chain should be replaced.

If you only replace the chain and not the gears, the chain may skip. For this reason, it is best to replace both at the same time (the front gears are not as affected by this because they are bigger and the chain doesn't pass over each tooth as many times). Replacing the chain more often, when 11 links measure 11 1/16" (281 mm), will allow the gears to be reused.

Avoiding Chain Wear
To prevent such wear, avoid using gear combinations that stretch the chain diagonally.

Also change gears only when you are turning the pedals. Remember to gear down when coming to a stop.


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Bicycles/Maintenance and Repair/Maintenance Schedules

Regular bicycle maintenance
Performing regular maintenance on a bicycle will improve its performance and longevity, and reduce the risk of breakdowns. The exact schedule for a particular bicycle will depend on how it is used: its weekly mileage, the weather conditions, road (or off road) surface conditions and so on. Most parts will need attention and possible replacement every year or two; if this is done, however, a bicycle can be maintained in good working order for decades.

Bicycle inspection & maintenance can be roughly broken down into four categories. Each includes clean, inspect, adjust, lubricate and repair as necessary. The primary difference between them is the depth or level of each task and sub-task.

 * 1) Pre-ride
 * 2) Post-ride
 * 3) Tune-up
 * 4) Overhaul

The schedule given here is a starting point for an average bike, assuming daily or weekly use; you will soon adjust this based on your own experience.

Every ride: (washing with a bike cleaner helps get rid of dried on and hard to get off grime.)
 * Check that the tires are inflated (a quick pinch to ensure they are hard generally suffices)
 * Check both wheels will rotate without sticking
 * Squeeze both brakes to make sure they engage properly (this is especially important if you have been working on the bike and may have disconnected the brake cables)
 * Check for obvious loose parts; if you have panniers or removable child seats make sure they're properly attached
 * Check you have working lights, a lock and a key if you will need them before you return
 * After the ride, if the moving parts have got muddy or picked up road salt, give the bike a quick hose down. It's much easier doing it now than after it has dried!

Once a week:
 * Lubricate the chain
 * Re-inflate the tires to the correct pressure.
 * Rotate wheels to check that they are in true. Replace any broken spokes - other spokes will break and the wheel will be permanently bent if ridden in this condition.

Quarterly:
 * Check the brakes to ensure they are correctly adjusted, and that the pads are not worn.
 * Check derailleur adjustment.
 * Check screws or bolts holding attachments such as mudguards, racks, bottles etc. are tight.
 * Check brake and gear cables for fraying or rusting, and lubricate.
 * Grease seat post. It may not technically be a moving part, but it is not desirable for it to become permanently stuck.
 * Adjust the saddle height and position if necessary. (when crank arm is in-line with seat tube and ball of foot is inline with pedal axle, knee should be slightly bent, then place heel on pedal, leg should then be completely straight. Hips should not wobble when riding bike, Lower seat if this occurs)
 * Check tires for signs of wear, bulges or splitting. (replace immediately)
 * Check handlebars are aligned properly with front wheel.
 * Check reflectors (if required) are still attached
 * Check the chain for wear

At least every two years:
 * Replace the chain and front or rear sprockets
 * Complete dis-assembly, cleaning, and lubricate all moving parts.
 * Check bottom bracket and wheel hubs for excessive play and replace if worn.
 * Check derailleur jockey wheels for wear, replace them if worn. *TIP* If the "teeth" of the jockey wheels or front or rear sprockets look sharp and pointy, Replace. (if rear cassette is worn, you will need to replace chain at the same time)
 * Grease metal-to-metal contact points.
 * Check saddle for splitting, and handlebar grips or tape for perishing or fraying
 * Check headset; tighten or replace bearings as necessary

Manual de la bicicleta/Mantenimiento de la bicicleta


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Talk:Bicycles/Maintenance and Repair

Revision history

Legend: (cur) = difference with current version, (last) = difference with preceding version, M = minor edit

* (cur) (last). . 23:11, 4 Jan 2004. . Egil (Moved to Wikibooks) * (cur) (last). . 12:11, 4 Jan 2004. . Egil (Move to Wikibooks?) * (cur) (last). . 16:15, 20 Dec 2003. . Dhodges (changed tires to rims in wheel truing. The tires are *off* when truing) * (cur) (last). . 04:17, 20 Dec 2003. . Morven (another renaming) * (cur) (last). . 04:14, 20 Dec 2003. . Morven (yearly maintenance page renamed; fixing link to fit) * (cur) (last). . M 06:08, 14 Dec 2003. . Infrogmation * (cur) (last). . 06:00, 14 Dec 2003. . Jwpurple (Most parts on bicycles are not interchangeable. e.g. 700c tires vs 27", US vs metric threads, etc.)   * (cur) (last) . . 05:48, 14 Dec 2003 . . Dhodges    * (cur) (last) . . 05:46, 14 Dec 2003 . . Dhodges (ft #Tire Levers#Pump)    * (cur) (last) . . M 13:05, 12 Mar 2003 . . Stephen Gilbert    * (cur) (last) . . M 12:35, 12 Mar 2003 . . G (the --> they)    * (cur) (last) . . 12:26, 12 Mar 2003 . . 217.158.229.141 (removed line)    * (cur) (last) . . 12:24, 12 Mar 2003 . . 217.158.229.141 (simple enough for many bicycle user to make simple repairs to their own vehicles.)    * (cur) (last) . . 12:22, 12 Mar 2003 . . 217.158.229.141 (')    * (cur) (last) . . 12:22, 12 Mar 2003 . . 217.158.229.141 (This article describes 'bicycle repair techniques.)    * (cur) (last) . . 12:03, 12 Mar 2003 . . Egil (Finally a lexicon that tells how to actually repair a bike)    * (cur) (last). . 00:31, 11 Mar 2003. . Statkit1 (more repairs added) * (cur) (last). . 20:56, 10 Mar 2003. . Statkit1 * (cur) (last). . 20:55, 10 Mar 2003. . Statkit1

Accessories
I'm of two minds about including a section on accessories (someone else put it on the main page). There are a few pieces of advice that can be offered. Still, with the great variety of accessories out there I'm most inclined to say RTFM.Dhodges 00:33, 13 Jan 2004 (UTC)

Organization
I'd like to propose a reorg of this into:

 * Tools
 * Supplies
 * Basic Tasks (where things like removing pedals go)
 * Repairs
 * Maintenance tasks

with a distinction that a Repair gets you back on the road, a Maintenance task improves something that's degraded, and a Basic task is a component of either of the above.

 * Nice to see someone else taking an interest. I'm more concerned with getting actual repairs written up, but hey go for it. Dhodges 22:27, 10 Mar 2004 (UTC)

Commuting bike
It's perhaps outside the scope of this book but I'd like to put together some advice for selecting a commuting bike. The content would go well alongside advice for fitting mudguards, fitting rear racks and other commuting essentials. Would you like to add a section for me to get started? --DavidBoden 19:12, 12 August 2005 (UTC)

Illustrations
Text only is a bit hard to follow, we could do with some more pictures (like on the spoke wrench). I've some tools at home, so I could do a few pictures, but only of the basic stuff. MWF 09:20, 12 Aug 2004 (UTC)

Diagram(s) with labels needed.
Thanks great start. I repaired my friend's bike like most of us do. Found very brocken sprocket in rear derailer (one of the two where the chain does the S bend, where the slack is taken up), removed it, with it in hand asked for a replacement at a bike shop, and was told I had to buy the whole rear derailer unit!! Until owner came out and pulled out recycled replacements. Inoperable bike totally fixed. Cost me $2. I didn't RTFM. Under most circumstances I like to have a diagram and name of the part so I appear to know what I am talking about, or can show I have made an attempt to research. Looking and sounding like a newbie can be very expensive. I hope someone can put in a diagram of the typical gear change bike with labels of parts to make phone calls easier.

Organization
Wouldn't it be better to organize the book based on the part of the bike being repaired rather than the skill level needed to perform the repair? Ex: Chapter 1: Wheels, Chapter 2: Brakes, Chapter 3: Drivetrain, etc. Each repair could also then be given a difficulty rating, such as on a one to ten scale, as well as a list of tools needed for the repair (a master list of tools at the beginning or end would still be helpful). I believe this is how most repair manuals are written and I almost just did it, but I decided it would be better to discuss it here first. --FurciferRNB 10 October 2005
 * I'm an utter newbie here, but that seems very sensible to me. --Danny Wilde 14:38, 16 October 2005 (UTC)

 * I think it might be useful to provide both an index by part and the old system that broke tasks up by difficulty and the frequency they need to be performed. The current system is more useful as a reference when your bike breaks, but the old way is more useful to a beginner who wants to learn or buy tools. --Dmonego 04:47, 11 November 2005 (UTC)

 * It seems like we almost need two 'streams' for the maintenance/repair part of the book: a reference manual that can be 'dipped into' at any point, and a learn-about-your-bike sort of book, which reads well cover-to-cover and incrementally introduces bicycle parts and concepts. A organisation that lets the reader go quickly to the bit they need isn't any good for someone who doesn't know what they need.  Similarly, the more experienced mechanic just wants to look something up doesn't want to trawl through all the 'this is a chainring' introductory material.  --Samwilson 02:32, 13 September 2006 (UTC)

Reorg
Based on input above from FurciferRNB and Danny Wilde as well as my own consensus, I've reorganized this book to reflect part-groups of a bike rather than difficulty level of the task. I think that this way users will more easily be able to find the information they're looking for. I still think difficulty should be reflected though. I suggest that sections in each chapter should be listed in order of difficulty from easiest to hardest. For example, in the chapter on 'Tires & wheels', 'Fixing a flat' would come before 'Truing a wheel.' I moved the listing of tools and supplies to its own chapter and I moved the manufacturer links to the Appendix.

Also, I reorganized the Bicyles page, of which this page is (has been) a module. I see this page, as well as those listed with it on the Bicycles page, as volumes in a library, where each volume should be able to stand on its own as much as possible.

With respect to DavidBoden's comment about equipment for a commuting bike, I think that information would go well in the volume on 'Equipment & accessories'. I'd also, personally, like to see more info on this topic, with maybe focus on what type of riding you do (i.e. commuting, touring, MTBing, BMXing, etc.)

Lastly, I've cleaned up this discussion page a bit to make the threads easier to read. Overall, I'd love to see some feedback and improvements on this book's reorganization. Thanks. Mindfrieze 18:12, 6 November 2005 (UTC)

Company Specific Manuals
--Georgio8 (talk) 15:15, 18 March 2010 (UTC) I notice that the Appendix has a list of links to Company Specific Manuals.

Some members of the Moulton Bicycle Club (moultonbicycle yahoo list) would like to use this book itself as a place to hold information that we have collected but haven't yet posted anywhere about the maintenance of the (many) different models of Moulton. So we're wondering whether it would be in the spirit of this book to add a Moulton section to the Appendix.

 * Georgio8, I say go for it. This hasn't been a very active book over the last five years, so drop your info in, and we'll see how it works out.  --Mindfrieze (talk) 14:34, 29 June 2010 (UTC)

title: Talk:Bicycles/Maintenance and Repair


text:
Talk:Bicycles/Maintenance and Repair/Wheels and Tires/Fixing a flat

Revision history

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* (cur) (last). . 23:14, 4 Jan 2004. . Egil (Moved to Wikibooks) * (cur) (last). . 12:11, 4 Jan 2004. . Egil (Move to Wikibooks?) * (cur) (last). . 23:52, 12 Dec 2003. . Mrzach (added sandpaper) * (cur) (last). . 23:46, 12 Dec 2003. . Mrzach (added step 1 (the easy way)) * (cur) (last). . M 05:38, 27 Nov 2003. . Dori (dont -> do not) * (cur) (last). . 01:38, 28 Mar 2003. . Marj Tiefert (spelling, grammar, commas) * (cur) (last). . 21:03, 2 Mar 2003. . G-Man

I believe the word tire has been inadvertantly substituted for tube in many places in the following paragraph which is found at the end of the notes section under Flat Repair. I placed (TUBE) where there appears to be an error.

"Because tire(TUBE) prices have come down dramatically, it is generally suggested to replace the tire(TUBE) after one patch job, especially for high-pressure tires. You should still have a patch kit or spare tube with you on long rides. You can cut the old tire(TUBE) into strips of rubber and use it for a variety of things, including bungee-type straps."

Unfortunately, I disagree with this comment. While it may be less expensive to an individual to replace a tube after one patch, the cost to the environment is heavy in materials and energy for every tube produced. My experience is that a tube can be patched many times before it's ready to become a bungee cord.

Ontario fuel stations seem to go above 35 psi
Pumps at fuel station only inflate to 35 psi? In Ontario, the pumps at fuel stations seem to inflate quite well and, often better than the mini-pump that I carry with me. WbZurp 14:31, 25 July 2005 (UTC)

It is better to carry a small pump than to look around for a service station pump, unless you don't have a flat. The 35 lb. statement isn't correct. It's easy to (b o o m !) blow out a tyre with a high pressure pump. There is no standard: there may be no air at the service station. If it's there, it may cost or be free and its pressure can indeed be too low. So what's said is essentially correct: it might not be a good idea to count on the gas station.

Suggested amendment which may alter sentence sense
I was wondering whether the sentence "the material to repair a tube is tiny compared to the entire tube itself" should be changed to "the cost of the material to repair a tube is tiny compared to the cost of the entire tube itself"...? Or is this is the sense that the author intended. Forgive me for being pedantic but as a writer I know how annoying minor edits can be if they change the sense of your sentence!

Your instincts are correct. Don't feel shy about making such corrections yourself. Dmforcier (talk) 21:30, 3 February 2008 (UTC)

Best structure for this topic?
There are several scenarios in which one might need to fix a flat: in the shop, on the road, with a road bike, with a MTB, using a patches or a whole tube, etc. The article was originally written for the type of bike with which the author was most familiar, and in a first-person style. So a couple of questions: Dmforcier (talk) 21:30, 3 February 2008 (UTC)
 * 1) Do we want to keep the first-person style?
 * 2) Covering all options in one set of instructions can be confusing. Should there be different sets of instructions for each scenario?

Working on it
Started working on this page. If there are comments of interest, now is the time. Does anybody know about an outer tire rubber filler that will bond to the cladding for fixing tears? It seems like something that would sell! You can boot the inside but most would be happier fixing the outsides too. (Reduced water ingress.). Thanks all, Armchair (talk) 16:56, 13 September 2009 (UTC)


text:
Talk:Bicycles/Maintenance and Repair/Wheels and Tires/Truing a bicycle wheel

Revision history

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* (cur) (last). . M 22:45, 4 Jan 2004. . Egil (This page has been moved to Wikibooks) * (cur) (last). . 22:44, 4 Jan 2004. . Egil (This page has been moved to Wikibooks) * (cur) (last). . 12:12, 4 Jan 2004. . Egil (Move to Wikibooks?) * (cur) (last). . 06:26, 14 Dec 2003. . Jwpurple (Fix a badly bent rim and eccentricity. Patience...) * (cur) (last). . 06:11, 14 Dec 2003. . Jwpurple (Folding rule as a trueing alignment tool.) * (cur) (last). . 13:44, 7 Mar 2003. . 217.24.129.50 (italic The Bicycle Wheel) * (cur) (last). . 13:02, 7 Mar 2003. . 212.24.80.69   * (cur) (last). . 13:00, 7 Mar 2003. . 212.24.80.69   * (cur) (last). . 12:53, 7 Mar 2003. . 212.24.80.69   * (cur) (last). . 18:22, 5 Mar 2003. . 212.24.80.69   * (cur) (last). . 18:20, 5 Mar 2003. . 212.24.80.69 (How to true a bicycle wheel)

What is lateral true & what is vertical true?
Lateral true & vertical true need to be defined in the article. —72.72.41.158 21:22, 27 May 2007 (UTC)


text:
Talk:Bicycles/Maintenance and Repair/Brakes/Adjusting Rim Brakes

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* (cur) (last). . 22:52, 4 Jan 2004. . Egil (Moved to Wikibooks) * (cur) (last). . 12:10, 4 Jan 2004. . Egil (Move to Wikibooks) * (cur) (last). . 14:58, 3 Jan 2004. . Egil (Up for deletion) * (cur) (last). . 03:56, 3 Jan 2004. . 68.228.42.110   * (cur) (last). . M 08:19, 22 Dec 2003. . Angela (bold, link) * (cur) (last). . M 03:16, 29 Aug 2003. . Zack * (cur) (last). . M 16:15, 13 Aug 2003. . Andrewa (fix link) * (cur) (last). . 15:58, 13 Aug 2003. . Andrewa (add details of cables) * (cur) (last). . 15:52, 10 Mar 2003. . AndyGates

Picture of bike showing parts...
Hi, I put on january a picture, can you help me to find it Thanks... --Gengiskanhg 23:42, 14 Apr 2005 (UTC)

 * Hi, that image was probably added before the page was moved from WIKIPEDIA.  This history only starts on the beginning of January 2005.    If you know some part of the name of the image it might be found in MAYFLOWER IMAGE SEARCH.   Armchair (talk) 20:00, 5 July 2009 (UTC)

Other brake problem causes
Please leave a note here if you know of other brake problems that may be of interest for the page.

Alternatively, add a section.

Armchair, 16:20 GMT, 27 September 2009

Simplicity
The page starts with "The brakes on bicycles are simple to adjust.", which already made me laugh. Then a couple paragraphs later:

 * Bear in mind that the best way to learn the adjustment of brakes is to be shown by somebody while it is being done; in this way much of the mystery vanishes.
 * The next best way is to follow a fairly stolid description of the sort below, which will get the job done with a little perseverance.

I see a certain contradiction in the lead. I would remove the first sentence. --Chealer (discuss • contribs) 01:15, 6 October 2011 (UTC)

Hi, Whereas you say that you would remove a sentence, I also note that you did not! So pleased that my efforts amuse you - a little more effort and a bit less idle commentary would serve you and the writing community better!Armchair (discuss • contribs) 08:34, 27 December 2011 (UTC)

Noodle
Super page. The pipe marked "cable guide" is a noodle, and the rubber item marked "noodle" is actually a boot

 * Correct. I've edited the page, though I note that my edit is awaiting review. I made a similar correction to Cables and Housings (also awaiting review). Geordiecoder (discuss • contribs) 13:40, 26 December 2015 (UTC)


text:
Talk:Bicycles/Maintenance and Repair/Chains/Mending a broken chain

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* (cur) (last). . 23:05, 4 Jan 2004. . Egil * (cur) (last). . 12:13, 4 Jan 2004. . Egil (Move to Wikibooks?) * (cur) (last). . 02:35, 20 Dec 2003. . Dhodges (mending a chain)


text:
Talk:Bicycles/Maintenance and Repair/Maintenance Schedules

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* (cur) (last). . M 23:08, 4 Jan 2004. . Egil (Moved to Wikibooks) * (cur) (last). . 23:07, 4 Jan 2004. . Egil (Moved to Wikibooks) * (cur) (last). . 12:13, 4 Jan 2004. . Egil (Move to Wikibooks?) * (cur) (last). . 18:34, 24 Dec 2003. . Dhodges (added to "every two years" maintenance) * (cur) (last). . 15:58, 20 Dec 2003. . Dhodges * (cur) (last). . M 04:36, 20 Dec 2003. . Infrogmation * (cur) (last). . 02:29, 20 Dec 2003. . Dhodges * (cur) (last). . 02:26, 20 Dec 2003. . Dhodges (section on yearly maintenance)


text:
Dutch/Cover

Begin the Wikibooks Dutch Language Course!

title: Dutch/Cover


text:
Dutch

=Welcome!= Welcome to the Dutch language course. Notice the arrows under the images of a number of cities where Dutch is spoken? Click on the arrow to hear how their names are pronounced in Dutch. There may be some surprises!

Information about the course
If you want more information on the course, here are a few pages that may give you that.

The lessons
If you want to jump right in and start learning: there are three types of lessons:
 * 1) Main lessons concentrate mostly on conversations to introduce grammar
 * 2) Practice lessons concentrate mostly on practicing grammar, vocabulary building, listening, quizzes
 * 3) Cultural lessons teach language the fun way. Songs, stories, poems, videos etc.

There are three levels, each consisting of two cycles of four lessons each.

Beginner level
At the end of this level learners should be able to form simple sentences in the basic tenses and possess a vocabulary of just over 1000 terms.

Intermediate level
At the end of this level learners should be able to deal with complex sentences with complex verbal expressions and have a reasonable grasp of syntax.

Advanced level
At the end of this level learners should have full command over Dutch grammar and syntax, including a number of special topics.

Special lessons

 * This course is mostly based on (northern) standard Dutch, but it will at times go into the differences with other varieties. There are two special lessons that consider the relationship of northern standard Dutch with Afrikaans and Flemish

 * Afrikaans — Comparison with Afrikaans, the language of South Africa and Namibia, and derived from Dutch.
 * Until 1928 it was seen as the same language as Dutch. Then both Dutch and Afrikaans became official languages of South Africa. Dutch ceased to have that role in 1961.
 * Afrikaans has its own wikibook, if you wish to learn it.

 * Vlaams — Flemish is a special case, not a language and not a dialect. It is commonly spoken in Flanders but has no official status or anything comparable.

Appendix

 * Een — Het alfabet ~ Dutch alphabet and Pronunciation Guide
 * Twee – Zinnenboek ~ Common phrases in Dutch (Book of Sentences)
 * Drie – Pronouns
 * Vier – Websites
 * Vijf – Hoe laat is het? ~ Asking the time''
 * Zes –  Handig - Handy links - Newspapers in Dutch (& Afrikaans)

Under construction
/For children/

Nederlands Niederländisch Néerlandais Hollenska הולנדית Dorerin Eben Eyong Nederlands Niderlandzki Мова людства/Нідерландська

title: Dutch