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  1. Bicycle Repair Manual - Chris Sidwells
  2. Barnett's Bicycle Repair Manual - eSense - PDF Drive
  3. Bicycle Repair Manual - Chris Sidwells
  4. Bicycle Repair & Maintenance

Bicycle Repair Manual - Chris Sidwells - Free ebook download as PDF File .pdf), Text File .txt) or read book online for free. bicycle have more specific terminology and definitions. For the purpose of this manual, the following terms apply to the frame and basic components. Frame: The. The Bike Repair Manual will help you avoid such problems by demonstrating how to maintain your bike regularly and correctly. Understanding technology.

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Bike Repair Manual Pdf

Chain. Chainguard. Bottom Bracket. Crankset. Pedal. Mudguard Stay. Handlebar . Stem. Headset. Lamp Bracket. Mudguard. Valve Stem. Spoke. Fork. Front Hub. how to maintain and repair bikes, not just from within the comfort of a well- stocked suspension forks, check your owner's manual for instructions on how to. Bicycle maintenance made ridiculously easy. From zero to hero all the things an absolute beginner needs to know to look after their own bike. Checklists.

Do the same with linked. If your gears are not shifting any new equipment that you download. Manuals will while riding to see what is causing help you to be aware of the particular the problem. As a result, you might maintenance requirements of all the take your eyes off what is happening components on your bike. The bike mechanics, there are many Bike Repair Manual will help you magazines available that contain avoid such problems by demonstrating tips on specific components. However, how to maintain your bike regularly the large majority of people who are and correctly. However, cycle components work, The different maintenance requirements as they have always done, according to of the most common types of bike are logical principles, so there is no reason listed at the beginning of the book. These requirements are covered in the Before you begin to service a step-by-step pages that are specific particular component of your bike, to the components fitted to each type first become familiar with the part of bike — for example, suspension forks by turning to the relevant section. Knowing how a part works makes it You will also find a timetable for easier to maintain. Even if you identify and solve problems. The book do not think of yourself as mechanically helps you to spot danger signs and to minded, you may come to enjoy bike carry out routine safety checks. These maintenance after a time and will features detail what you need to do certainly enjoy the trouble-free and refer you to the relevant step-by- cycling that rewards your efforts. Identify all the different parts and components to help you see how they work together as a whole.

Replace the rim if you see these signs. Check each tyre for splits or cuts in the tread or Look closely at the tread of both tyres for signs side walls. A large split means that the internal of wear. If the tread is worn, the tyre has lost fabric of the tyre is damaged, so the tyre is likely structural strength and can break down and to blow out. Smaller splits and cuts will let sharp distort or bulge.

The result can be a blow-out objects penetrate the tyre, causing at least a during the course of a single ride. A tyre that has puncture and possibly a rapid blow-out. Replace been skidded and lost enough rubber to develop a the tyre if you see any splits or cuts see pp.

Replace the tyre if you see either sign see pp. Preparing for wet weather These steps will help you to prepare a bike bike. Regular cleaning and lubricating helps for the rigours of winter, a particularly wet with protection, but try to stop the mud climate, or if most of your riding is done and salt from reaching the delicate parts off-road.

The mud, sand, and water that your of the bike in the first place. The overall wheels spray up into every part of the bike aim when protecting a bike in winter is to combine to form a damaging, grinding paste.

Protecting a bike Fit mudguards, insert seals, and lubricate the exposed parts to Mudguard protect a bike from wet conditions. Headset Mech Seat post collar. Shielding exposed components Sealing the seat post collar Sealing the headset. Keep water out of the point where the seat pin Place a cover over the headset to provide enters the frame. Mark this junction and remove protection.

You can fit a protector to the headset the pin. Pull a piece of narrow road bike inner tube without removing any components by simply over the frame. Insert the pin through the tube to joining up the velcro. Preparing for wet weather Fitting mudguards Fasten a mudguard to the seat pin and you will block much of the spray from the back wheel.

For the front wheel, fit a guard that clips on to the frame and is secured in place with tie-wraps. Full mudguards, which attach to the fork and rear drop-out, give almost full protection for on-road biking but get clogged up off-road. Weatherproofing the transmission Cleaning and lubricating the chain Cleaning and lubricating mechs. Lubricate and clean your chain as often as Dribble oil on to the pivots around which the you do in summer and after every wet ride.

Use a heavier, wet oil Apply the same light lubricant that you use in rather than the oil you would normally apply the summer and then apply a heavier oil, which during the summer. Every time you dribble oil like will not wash off as easily. Only coat the rollers this, first flush out the old oil by dribbling some and insides of each link with heavier oil because degreaser on to the pivots and letting it sink in it attracts more dirt. Cleaning and lubricating pedals Apply heavier, wet oil to lubricate the retention mechanism of clipless pedals after degreasing all the moving parts.

The heavier oil will not wash off as easily as dry oil. Regularly clean off old oil with degreaser and apply new oil in order to prevent the accumulation of grit and the consequent increase in pedal wear. Fine- tune and regularly service the system to ensure that the gear-shifters, chain, chainset, cassette, and mechs work together in perfect harmony.

Cables are under constant tension and need to be replaced regularly and kept well lubricated. They must also be inspected often and replaced if they show signs of wear. Shifters require only occasional lubrication of their inner workings.

How they work Controlling the gears The cables and shifters on a bike allow the rider An inner cable connects the gear-shifter to to effortlessly control the mech, and allows the rider to change the gear system. Gear-shifts made by a gear shifter cause the front mech to shift the chain from one chainring to another, or the rear mech to shift the chain from one sprocket to another.

Pulling the gear cable shifts the chain from a smaller to a larger chainring or sprocket; releasing the gear cable shifts the chain from a larger to a smaller chainring or sprocket. The left-hand shifter controls the front mech; the right-hand shifter controls the rear mech. Cable clamp Attaches the cable to the rear mech. Rear mech Moves the chain from one sprocket to another.

Bicycle Repair Manual - Chris Sidwells

A clamp connects the cable to the rear mech. When the shifter is pushed, the cable pulls the rear mech inwards, moving the chain from a smaller to a larger sprocket. When the shifter releases the cable tension, the springs on the rear mech pull the jockey Front mech Moves the chain wheels, and the chain, back to from one chainring a smaller sprocket.

In this Campagnolo shifter, the rider pushes the inner shift lever to pull the cable and move the mech. When the rider depresses a lever on the inner side of the lever hood, the cable is released and the mech moves back. Gear-shifter Pulls and releases the gear cable. Gear-shifters are often combined Lever hood with the brake levers on the Attaches the levers to the handlebar handlebar. On this Shimano gear- shifter, the brake lever also acts as a shift lever. When the rider Ratchet Cable pushes the brake lever inwards mechanism Connects Holds the the shifter with the fingers, the control cable to the rear cable attached to it is pulled and mech a ratchet mechanism is lifted.

A click of this mechanism equals one shift of the front or rear mech, which moves the chain Cable inner Controls a mech across the chainring or sprockets. The ratchet mechanism then Inner shift lever holds the cable in its new Releases the cable position. Drop handlebar Replacing a Shimano gear cable gear cables Keeping gear cables clean and lubricated, and replacing them if they fray, is very important for smooth shifting.

Change them as a matter of course at least once a year, or more often if you are a heavy user. Lubrication reduces the effects of friction between the inner cable and the cable outer, and helps to keep out water and grit.

If the gears become difficult to shift to a different chainring or sprocket, the cable is probably dry and needs lubrication. Friction increases with cable length. Cut Place the gear-shifter in the smallest cable outers as short as possible, but not so short that they constrict the cable or restrict 1 sprocket for the rear shifter and the smallest chainring position for the front shifter.

Parts of gear-shift units Rubber brake Campagnolo Ergoshift hood cover Brake lever. Insertion point of gear cable concealed by lever hood.

You also need to -shift lever do this if you are replacing a brake cable. Pull the tape off slowly. Drop handlebar gear cables Pull the gear cable 2 through pre-cut lengths of cable outer with the long-nosed pliers. Then tighten the bolt with the Allen key. Put the rear shifter in the smallest sprocket Dribble oil into a cable outer, which should 2 and the front shifter in the smallest chainring. Keep the cable to the mech under tension as you clamp it.

Straight handlebar Replacing a Rapidfire gear cable gear cables Looking after and replacing the gear cables on a mountain bike is very similar to a road bike. However, mountain bikes are often subjected to harsher conditions than road bikes, as they are often ridden through dirt and mud, so the cables must be replaced and lubricated more regularly.

Take special care if your mountain bike has cable disc brakes because they have longer lengths of cable outer and the cables require lubricating more often. Gear indicator. Gear shift Handlebar clamp lever Shimano Cut both the cable and cable outers with Cable port Dual Control 3 your cable cutters to the same length as the Brake lever body old ones you have removed.

Make the outers long Shifter body enough to allow the cable to travel freely inside. Straight handlebar gear cables Replacing a Grip Shift gear cable. Push the cable into the hole until its end For the rear cable, put the shifter into the 2 shows through the barrel adjuster on the 1 smallest sprocket. For the front cable, put outside of the shifter body.

Replacing a Dual Control gear cable. Thread the inner cable through each For the rear cable, put the shifter into the 4 length of outer cable.

For the front cable, put the front shifter into the smallest chainring. Cut off any excess cable. The mech pivots and jockey wheels must be checked for wear and lubricated. The front mech must be properly aligned with the chainrings. How they work Rear mech Transfers the chain from The front and rear mechs change the gears on a bike.

To one sprocket to another change up a gear, the shifter is used to pull on the cable, which causes the front mech to push the chain from a Cable smaller to a larger chainring or the rear mech to push Pushes and the chain from a smaller to a larger sprocket.

To change pulls the rear mech down a gear, the cable is released, causing the springs in both mechs to move the chain to a smaller chainring or sprocket. Each mech moves around a pivot point.

High and low adjusting screws ensure that the mechs do not push the chain beyond the largest chainring or sprocket, or pull it beyond the smallest.

Once its travel is set up, and provided the cable tension is sufficient, the mech will make a single, clean gear-shift for every click of the shifter.

To change gear, two jockey wheels transfer the chain on to a different sprocket. They move in the same plane as the chain and are spring-loaded to preserve the tension in the chain. Two mech plates enable the jockey wheels to change gear upwards, while the plate spring enables the jockey wheels to change gear downwards.

Mech plate Transfers cable pull to the jockey wheels. Plate spring Pulls the mech back as cable is released.

High and low Jockey wheel spring adjusters Preserves the Limit the travel tension in the chain of the mech Jockey wheel Working with the shifters Cable clamp Pulls and pushes The front and rear mechs work Attaches the cable the chain in harmony with the shifters to the mech plates Jockey wheel cage to provide easy, quick, and Cable Holds the jockey accurate gear-shifts whenever Pulls the mech plates wheels the rider needs them.

When the cable is pulled, it causes both the mech plates to swing inwards on four pivot points, causing the jockey wheels to guide the chain on to a larger sprocket. When the cable is released, the plate spring moves the chain back to a smaller sprocket. Large sprocket The chain is Small sprocket The chain is moved to the largest sprocket returned to the smallest by the pull of the cable.

When pulled, the cable moves the outer arm, which acts like a lever on a pivot point to push the front mech cage away from the bike. This moves the chain from a smaller to a larger chainring. High and low adjusters Clamp bolt Limit the travel of the mech cage Fixes the mech to the frame Outer arm Acts as a lever Cable clamp Holds the cable to the mech. Pivot point Acts as a fulcrum for the arm. Front mech Chainring Transfers the Carries Mech chain from the chain cage one chainring Moves the to another chain.

There are two main kinds: There are two important maintenance jobs for a front mech: You should also clean the mech regularly to prevent the build-up of dirt, which interferes with the way it works and will quickly wear it out.

Note the distance by which the lower edge of its be parallel with the chainrings. This should Correct shifts depend on the front mech be 2mm.

If it is more or less, undo the frame- travelling a certain distance per shift. High fixing clamp and raise or lower the front mech. Front mech cage outer side Frame-fixing clamp Pull the gear cable through the cable 3 clamp and tighten the cable-clamp bolt.

Undo the cable- 2 fixing clamp until the cable becomes free. Use degreaser, and then wash and dry the whole area. Shift the chain across until it is in the Screw in the high adjuster usually marked 4 smallest sprocket and the largest chainring.

Rear mech Adjusting a rear mech Most rear mechs are indexed, which means that for every click of the shifter, either up or down, the mech will shift the chain from one sprocket to the next.

Occasionally, you may find that the chain does not quite move on to the next sprocket when you make a single shift, or else it skips a sprocket in an overshift.

In either case, the rear mech needs adjusting. You will also need to follow the steps in this sequence whenever you fit a new cable see pp.

To ensure that the rear mech works faultlessly, pay particular attention to its jockey wheels because this is where oil and dirt can accumulate. Degrease and scrub Shift the chain on to the biggest chainring them every time you clean your bike see 1 and smallest sprocket, then undo the pp.

Whenever you lubricate the jockey cable-fixing clamp so that the cable hangs free. Barrel Cable-fixing adjuster clamp. Jockey cage Shift back to the smallest sprocket, then Jockey wheel 4 shift upwards through each gear. If the rear mech does not shift all the way on to the next biggest sprocket, screw out the barrel adjuster until it does.

If the mech over-shifts and skips a sprocket, screw in the barrel adjuster until it stops. Prevent the jockey wheels 5 from making contact with the bigger sprockets by screwing in the adjuster that butts on to the rear mech hanger on the frame drop-out. Remember to make this adjustment if you fit a block or cassette with bigger sprockets than usual. They require little routine maintenance and, since they are sealed, most hub-gear systems do not need to be lubricated regularly.

The control cables must still be inspected regularly and replaced if they are worn. How they work All hub gears work according to the same basic principle. A system of internal cogs make the hub casing, and therefore the rear wheel, turn at a different speed to a single, external sprocket that is driven by the pedals via the chain.

The sprocket is connected to the cogs by a driver unit and the cogs rotate the hub casing at different speeds. Spokes attach the casing to the rim, thereby revolving the rear wheel. A shifter on the handlebar operates a mechanism attached to the hub. This mechanism causes various combinations of different-sized cogs within the hub to engage with a ring gear, which drives the hub casing. Each combination gives a different gear ratio, and the number of gears depends on the number of cogs within the hub.

To change gear, the rider activates the shifter to containing cogs. Different cogs are brought into pull the cable, which turns the satellite on the contact with the ring gears. When the cable is drive side of the hub. This triggers a mechanism released, the spring-loaded carrier units move within the driver unit to move two carrier units the cogs back to a different combination.

Hub casing Turns the wheel. Cable and satellite Side view of the hub. Bearings Aid the rotation of the hub casing. Protecting the gears The hub gear mechanism is fully enclosed to protect it from damage, dirt, and water.

Hub gear I Replacing a hub-gear cable If the cable to your hub gear breaks or frays, you will need to replace it. This is usually stamped on the hub and the number of gears is indicated on the shifter. The hub-gear model illustrated in the steps of this sequence is the Shimano Nexus 7-speed gear, which is operated by a twist grip shifter. Alternatively, bikes may be equipped with SRAM hub gears, as well as those made by other manufacturers, that are operated by thumbshifters.

Some older bikes have Sturmey Archer 3-speed gears. Although they all work on the Put the shifter into first gear. At this same principle, the methods used to change 1 point, there is no tension on the cable, so a cable are subtly different.

Try to find the it is the starting point for fitting a new cable. Parts of a hub gear Seat for cable- retaining bolt Right-hand axle nut.

Cable route Insert the cable through the chainstay 4 cable guide and make sure that the outer is well-seated into the guide. Hub gear I Remove the rear wheel see pp.

Dribble a little oil inside the outer and then push Undo the clamp to remove it from the old cable. Return the wheel to the bike 5 by placing the axle in the rear drop-outs and pulling backwards on the wheel so that there is tension on the chain. Do not pull so hard that the chain becomes tight. If there is a problem, the hub gear may need adjusting see pp. You will need to remove the satellite to clean it and this means removing the rear wheel.

On other occasions, you might find that the shift has lost some of its smoothness. In this case, the cable has probably stretched so that the shifter is out of phase with the gear mechanism. To remedy this problem, use the barrel adjuster on the shifter to take up any slack in the cable.

Every time the wheel is removed and put back on to your bike, run through the gears and check that they are shifting correctly. Remove the rear wheel by undoing and If they are not, follow the last two steps of 1 removing both its axle bolts see pp. Turn the lockring by hand until its yellow dot lines Finally, the hub-gear system has clear up with the one on the satellite.

If a bike is fitted with a Sturmey Archer 3-speed hub gear, it may occasionally shift to second gear, but without any drive. When this happens, put the shifter into the third gear position and look at the cable where it runs along the chainstay. The cable will be slack so that it sags. Undo the cable-clamp bolt near to the hub-gear unit and pull the cable through the clamp until it runs in a straight line.

Re-clamp the bolt and the gears will shift perfectly. The satellite is now locked in place. Hub gear II Lift the satellite from 2 the hub body, noting the relative positions of the two yellow triangles that are marked on it.

Let this drain out and spray light oil into the satellite. Shift through the gears until the shifter Look for the two red dots on the gear 4 is in fourth gear. One is marked on the satellite and one on the lockring.

Tilt the bike so the underside of the gear where the cable runs. In fourth gear, these two dots should line up. If they do not, screw the barrel adjuster in or out until the dots line up. When they do line up, all the gear-shifts will be perfect. The parts are in continual contact, and the motion of pedalling inevitably leads to wear. No matter how well you look after each part, they will eventually need removing and replacing. The pedals drive the chainset and, via the chain, turn a sprocket attached to the hub of the rear wheel, which in turn rotates the wheel.

Bikes with derailleur gears use mechs to shift the chain on to different-sized sprockets and chainrings, which make up the cassette and chainset. Each combination of chainring and sprocket provides a different gear ratio, giving up to 27 different gears that can be used to tackle anything from Chain Feeds through steep climbs to gentle flats. The cassette transfers the motion of the chain Cassette body Quick-release lever to the wheel. It consists of sprockets that Contains the freewheel Locks wheel into slide on to the cassette body, which is bolted place on to the hub.

The cassette body houses the freewheel, which allows the wheel to turn when the cassette is stationary. Lockring Holds sprockets on the body. The chain is the key to Barrel transmitting pedal power Sits between teeth of into forward motion.

To achieve this, a series Shaped to allow of links articulate around joining quick gear shifts pins, which are surrounded by Inner link revolving metal barrels. Rotates around the barrel. Rear wheel Chainset Chainring Chain Pedal Driven by Powered by Carries the Transmits Transmits the sprockets pedalling chain around power from energy to the the chainset the chainset chainset.

Lightweight components The chain, cassette, and chainset are lightweight items that use the latest design and construction techniques to maximize strength and durability while maintaining an aerodynamic profile. Chains Replacing a derailleur chain Replacing a chain is a regular maintenance task. All chains eventually wear out, even if you clean and lubricate them properly.

A worn chain, as well as being inefficient, will quickly wear out other transmission parts, and so prove expensive. To determine how much a chain has become worn, either use a specialist gauge from a bike shop or measure the length of 24 links. If the length is greater than mm 12in , the chain is worn. New chains on derailleur gear systems are linked with a joining pin that comes with the chain.

You will need a link extractor tool to make this join. The thicker chains of hub Shift on to the smallest chainring and gears, BMX bikes, and some fixed-gear bikes 1 sprocket so that the chain is slack. Groove Split-link chain. Inner Remove the excess links from the opposite links Split pin 3 end to the one on which there is a joining link.

Leave an inner link so that the two ends can be joined together. Thread a new chain through the jockey Join the chain by pressing the side of the 2 wheels and around the biggest chainring 1 split link with the pins fixed in its plate and smallest sprocket. This establishes the length of chain you need. Loosen any stiff links that occur when the Push the split pin into the grooves of the 4 chain links are compressed during Step 3. These are sticking through the outer plate that you have just fitted.

Cassette and Removing a cassette freewheel The cassette and freewheel allow the rear wheel to rotate while the pedals remain stationary.

Their internal mechanisms — the freehub body of a cassette and the block in a freewheel — will eventually wear out and need replacing. The sprockets on both can also wear. These parts will also need to be removed whenever you replace a broken spoke on the drive side of the rear wheel. The tools for removing a freewheel and a cassette depend on the manufacturer of the part that is fitted to the bike. However, if you are in any doubt about which tool you need, take the wheel 1 the rear wheel.

Wrap the chain whip around a sprocket, Take off the smallest sprocket after 2 and place the spanner on the remover. This holds the cassette, while the remover unlocks the lockring.

If they do not, you must put individual sprockets back in a certain way. Usually, lockring starts turning. Put the spanner on the flats of the block Check the integral freewheel mechanism, 2 remover and turn anticlockwise. Chainsets Removing a chainset Removing a chainset is a useful skill to have because it will allow you to replace an old crank, clean or replace a worn chainring, or work on the bottom bracket. Chainsets are attached in one of four ways.

Those held in place by a hexagonal bolt can be removed with a chainset socket spanner see Step 1. Chainsets with a self- removing Allen bolt can be detached with an 8mm Allen key see Step 2. Versions with a standard Allen bolt can be detached with the relevant Allen key see Step 3.

Those on a hollow-axle bottom bracket can be removed by reversing the steps on pp. When refitting a chainset, keep grease or Detach a hexagonal chainset bolt from oil from touching the axle. The chainset must 1 the axle with a chainset socket spanner. After refitting, go for a short ride and then try the axle bolt again. Work from below the chainset so that if your hand or the spanner slips, the chainring teeth will not injure you. Right-hand crank. Chainring bolt Use a crank extractor to remove the Chainrings 4 chainset if it is not the self-removing type.

Make sure that the washer beneath the bolt has also been removed. Unscrew a self-removing Allen bolt with Use a long-handled Allen key if there is 2 an 8mm Allen key. These kinds of bolt 3 an Allen bolt holding the chainset on your extract the chainset as you unscrew them.

Usually, an 8mm key is the size required. Work from below slip the chainring teeth will not injure you. Remove the chainring 5 with a 5mm Allen key on one side and a chainring bolt peg spanner to hold the bolt on the other.

You can do this without taking the chainset off the axle, but you must remove it if you are working on the inner rings of some triple chainsets. Standard chainring bolts are made from steel. Be especially careful not to over-tighten aluminium or titanium bolts. Both use sealed bearings, which can wear out over time. If this happens on the cartridge version, replace the whole unit, but on a hollow-axle type you only need to replace the bearings.

Each type of bracket consists of an axle, two bearings, and two threaded cups called either the free cup and fixed cup, or the non-drive and drive-side cup. With the cartridge type, both cranks bolt onto the axle, but with the hollow-axle type, the drive- Providing strength side crank is fixed to the axle and only the non-drive side The axle and bearings of crank can be bolted on.

A third type of bottom bracket, the bottom bracket need to the BMX bracket, has a threaded axle — the bracket is be both strong and reliable held in place by a locknut that screws on to the thread enough to bear the weight on the non-drive side of the axle.

Each of the cartridge bearings is composed of ball-bearings, which are sandwiched between an inner and outer race by plastic seals. The cartridge bearings are located close to each end of the bottom-bracket axle. A tubular sleeve fits over the two bearings, filling the space between them. The fixed and free cups fit over this sleeve to create a Free cup totally sealed unit.

The drive-side crank is permanently fixed to the axle, which passes through both cups. The non-drive side crank slides onto the axle and is secured by two pinch bolts. The crank cap bolt inserts into the end of the axle to hold Pinch bolts the crank against the Hold crank bearing, ensuring that in place on there is no play, rather the axle like the stem cap bolt on a threadless headset p.

Crank cap bolt Cup Presses crank Holds the bearings against bearings in place in the frame Ball-bearing Lets the axle turn Axle Connects the cranks Cup together and rotates Crank Holds bearings in the bearings Turns the axle in the frame. Crank Turns the axle. Cartridge Installing a cartridge bottom bracket bottom bracket Cartridge bottom brackets require no routine maintenance.

Their bearings are sealed from the elements — even from the water you use for hosing or pressure-washing your bike, provided that you turn the pedals forwards during the wash. When the bearings do eventually wear out you will have to replace the whole unit. The remover tools for this job are specific to each particular bottom bracket, so check which make is fitted to your bike before downloading the tools.

If you are planning a replacement, there Put the bike on a workstand and remove are three types of bottom bracket axle to choose: You need to do Finally, if you are having any problems this because different chainsets are designed to installing a bottom bracket on your bike, work with different axle lengths.

Parts of a cartridge bottom bracket Drive fixed-cup side. Grease the threads of each side of the 4 new bottom bracket for easier fitting. The non-drive threads are sometimes referred to as Non-drive Bottom-bracket axle free-cup the free-cup and the drive-side threads are known side as the fixed cup.

Do not grease the drive side of a bottom bracket with Italian threads. Measure the width of the bottom-bracket Remove both the cranks see pp.

This width determines the remover anticlockwise with a spanner. Turn it anticlockwise if your bike has an Italian- threaded bottom bracket marked 36 x 1. Insert the bottom bracket from the drive 5 fixed-cup side using the remover tool.

Fit the teeth of the tool into the indentations of the bottom bracket see enlargement. Use the remover to screw it in a few turns. Fully tighten the drive side, then the non-drive side. Hollow-axle Installing a hollow- axle bottom bracket bottom bracket The hollow-axle system was developed to increase the strength of the bottom bracket. The bearings on which the axle runs screw onto the outside of the bottom bracket shell, which allows a large diameter axle to be used that is hollow, light, and stronger than other axles.

Since the bearings are further apart than on other types of bottom bracket, they encounter less torque, which increases their lifespan. However, they will still eventually wear and have to be replaced, so you will need to know how to remove and replace them.

You will also need to follow these steps if you want to upgrade to this system. The faces of the bottom bracket shell must 1 be flat and parallel. This requires specialist equipment, so get the frame checked at a bike shop. Combined Left-hand drive-side crank cup and sleeve Spacers.

Non-drive side cup Push the left-hand crank onto the non- Pinch bolt 4 drive side of the axle.

To do this, match the wide notch on the axle with the wide tooth on the crank. Put a little grease on the axle before you fit the crank. Hollow-axle bottom bracket Screw the cups into the frame as far as you Hold the drive side right-hand crank 2 can with your fingers inset. Grease the threads of the crank cap bolt, Tighten the crank pinch bolts with an 5 and screw it into place with your fingers.

Rotate the cranks and if the axle is stiff, loosen the crank the same amount. Repeat until both bolts are cap bolt a little. The biggest difference between this kind of BMX bracket and normal bottom brackets is that the threads securing it in the frame are on the axle and not inside the bottom- bracket shell. The axle has a cup and cone bearing system, a little like an open-bearing hub see pp. The drive-side cone, chainring, and axle are made in one piece, and the cranks bolt on to them.

This kind Take out the captive bolt at the centre of of chainset and bottom bracket is called a 3-piece chainset. Screwing the locknut on 1 the non-drive side crank, then loosen the crank bolt on the side.

Chainring Drive-side cone Non-drive side cup Non-drive side bearings Non-drive side cone. Put the newly greased drive-side bearings Drive-side Axle Axle threads 4 back into their cup, then insert the axle so bearings Spacing washer that it sticks out of the non-drive side.

Remove the crank. Hold the non-drive Take out the drive side of the bottom 2 cone still with a peg spanner while 3 bracket once you have removed the locknut removing the locknut with a spanner.

Replace any located inside the bottom-bracket shell. Replace any worn cups or cones. Put the non-drive cone and spacer over Put the spacer back on the non-drive 5 the axle and screw the cone on to the 6 side of the axle and then push the crank bearings with the peg spanner.

Screw the locknut back on to it. Then screw the cone back a little to the locknut. A bit of play in the axle is permissible, but too much will throw off the chain. Pedals with open bearings require regular inspection and lubrication. Clipless pedals must be lubricated to ensure easy foot release. They The body of a pedal rotates around an axle are the first step in the process of converting and is supported on bearings that are either human energy into open or held within a cartridge.

For example, studs that prevent foot slippage will help a rider who makes frequent stops, such as a commuter in heavy traffic. Some flat pedals are fitted with toe-clips and straps that hold the front of the foot, although they can interfere with the foot as the rider tries to remove it. Clipless pedals hold the foot securely, while releasing it easily whenever the rider wants.

A knurled Pedal body retainer attaches the pedal body Rotates on to the axle. The cone the axle not visible and the lockring can be Locknut Holds the adjusted to permit the free cone in place rotation of the body around the axle, without any play. Pedal axle Removing and lubricating a pedal axle The axle of a pedal is usually made from steel and the cranks from aluminium alloy. The tools to remove the axles are specific to the make of the pedals, and will be either supplied with the pedals or available at a good bike shop.

Most pedals contain two bearings on which the pedal body revolves around its axle. These sometimes need replacing; in the case of ball-bearings, they need regular cleaning, checking, and greasing. Place a spanner on the flats of the axle to Pedal axles can be damaged by an impact 1 remove a pedal.

Cleat-release Pedal body mechanism Pedal axle Retainer. Lift the axle from the pedal once you Spanner 4 have fully unscrewed the retainer nut.

Release tension If the axle is bent, it will need replacing. Hold the removed pedal, with the axle Ensure that the remover tool fits snugly 2 upwards, in a vice. The retainer may be damaged if you do not. Hold the cone with one spanner and remove Grease the inner bearing to prolong its 5 the locknut with another. The cone and 6 life. If it is worn, the whole axle assembly locknut hold the bearings on the end of the axle. To reassemble the pedal, repeat Steps 1—4 in reverse order.

Then lock the cone with the locknut. Clipless pedals Clipless pedals were developed in response and heavier oils on off-road pedals. The mechanism lets the foot pivot They hold the foot to the pedal by locking around its long axis during each revolution. The mechanism that holds the cleat to keep the mechanism working well.

Second, do not use too The guidelines below provide you with much force to tighten components — the general principles for some of the most nuts and bolts of lightweight parts can easily common tools or operations in bike repair.

Using Allen keys Using pliers Put the long axis of Use the short axis Use long-nosed pliers Fix a cable tidy on to an Allen key in the of an Allen key to to hold cables and a brake cable to stop Allen bolt to make the make the final turn keep them under the ends from fraying. download a small Push the cable tidy on for repeated turns and Allen bolt — for pair with pointed jaws to the end of the cable in places where space example, on a for tight areas. Keep and squeeze it flat is tight or restricted, chainring.

You can the jaws clean and with your pliers. If you such as putting a also use this technique grease-free. Lubricate are gentle, you can use bottle cage on the to start undoing an the pivot with light oil the inside jaws of your down tube. Allen bolt. Using a spanner Cutting cable outers Cut a brake cable Cut a gear cable outer between the outer through the spirals of the metal wire under the sheath.

If you need to, squeeze Always use the correct size of spanner for the If the spirals become the wire with the nut you are tightening or loosening.

The two brake pads do not contact the braking surface at the same time. The brake pads contact the braking surface without pulling the lever too far, but are ineffective at slowing the bike. The fork regularly reaches the limit of its travel bottoms out. The front wheel judders up and down when cornering. Strip down the cables, flush the outers with degreaser, clean the inners with degreaser, lubricate, and reassemble.

See pp. The cable has stretched or the relevant mech is poorly adjusted. Unclamp the cable at the mech, pull through any slack, and re-tighten. Then set up the mech. Either the chain has a stiff link; or the chain or sprockets, or both, are worn; or a chainring may be bent Check the chain for a stiff link and remove it if found. If no stiff link, replace the chain. If the problem persists, replace the sprockets.

If the chainring is bent, replace it. The bottom bracket is worn or its axle may be bent. If the bottom bracket is a cartridge type, replace it.

Barnett's Bicycle Repair Manual - eSense - PDF Drive

If it is a hollowaxle bottom bracket, replace the cup and bearing units. If it is a BMX bottom bracket, it may be possible to replace the bearings if they are worn, or to replace the axle if it is bent. The headset is loose or worn.

Strip and inspect the headset. Replace bearings if worn, regrease, and reassemble. Inspect the cups and races; if they are worn you should let a good bike shop replace the whole headset. A spoke may have broken. Replace the spoke and true the wheel. The hub bearings are worn or, in the case of tight and loose spots, the axle is bent. Replace the bearings or the axle. The freehub body is worn.

Replace the freehub body. Grit and dirt is inside the cable outers or the lubrication on the inner cables has dried. Strip down the cables, flush the outers, and clean the inner cables with degreaser, lubricate both, and reassemble. The pads are wearing down or the cable has slipped through the clamp bolt.

If the pads are not too worn, take up the extra travel by unclamping the brakes, pulling the cable through the clamp, and tightening. If the pads are worn, replace them. Your brakes are not centred. Follow the procedures for centring the type of brakes on your bike. There is grease on the pads, foreign bodies embedded in them, or they are wearing unevenly.

You may even need a different compound of brake pad. Rub the pads with emery cloth. Remove foreign bodies with long-nosed pliers. Fit new pads if they are worn unevenly. Seek advice from a bike shop regarding different pad compounds. Pump in more air. Replace springs with heavier duty springs.

The front of the bike is diving under braking because the fork is not stiff enough. Pump in air, or increase pre-load, according to the type of fork on your bike.

Insufficient air in the shock, or too much damping, means that the shock is not returning from each compression quickly enough. Set up the sag on the shock again. If the problem continues, use the damping adjustment to speed up the action of the shock. Replacing the parts as soon as they become worn not only keeps the bike running smoothly but also reduces the chances of an accident. You will save money, too, since worn parts have the knock-on effect of wearing out other parts. As you run through your safety checks see pp.

If you spot any danger signs, take action as soon as you can. You must replace a damaged part before you next ride your bike. Checking for wear Regularly check the tyres, rims, brakes, chainrings, cables, and sprockets so that you can spot signs of wear as early as possible.

Cables Rims and tyres Brakes Sprockets Chainrings Sprockets and chainrings Brakes Worn teeth Worn brake pads Regularly check for worn or missing teeth on a chainring or sprocket. The chain can jump when you apply pressure to the pedals, especially if you are out of the saddle, and you may be pitched forwards and crash.

Replace the chainring or sprocket as soon as you see this sign see pp. Regularly check all the brake pads for uneven wear. This is a sign that they are not contacting the braking surface evenly. Fit new pads and adjust your brakes correctly see pp. Spotting danger signs Cables Split or frayed cables Check all cables and cable outers for signs of splitting and fraying.

Frayed inner cables can snap, leaving you without gears, which is inconvenient, or without brakes, which is dangerous. Change the cable before you ride again see pp. Worn or split outers reduce the effectiveness of your brakes and allow dirt to get in and clog the cables. Change the outer as soon as you can. Rim brakes will gradually wear out the rims, especially if you ride off-road or in winter.

Eventually, the rims will fail and you could crash. Cracks around the nipples of the spokes where they join the rim are a danger sign, too. Replace the rim if you see these signs. Check the whole circumference of both tyres for bulges in the tread or the walls. Tyres with bulges or distortions are very likely to blow out if you ride on them.

If you see any of these signs, replace the tyre see pp. Split tyre Worn tread Check each tyre for splits or cuts in the tread or side walls. A large split means that the internal fabric of the tyre is damaged, so the tyre is likely to blow out. Smaller splits and cuts will let sharp objects penetrate the tyre, causing at least a puncture and possibly a rapid blow-out.

Replace the tyre if you see any splits or cuts see pp.

Look closely at the tread of both tyres for signs of wear. If the tread is worn, the tyre has lost structural strength and can break down and distort or bulge. The result can be a blow-out during the course of a single ride. A tyre that has been skidded and lost enough rubber to develop a flat spot can also be dangerous. Replace the tyre if you see either sign see pp.

The mud, sand, and water that your wheels spray up into every part of the bike combine to form a damaging, grinding paste. Salt, often used to treat roads where ice is likely to occur, will quickly corrode your Protecting a bike Fit mudguards, insert seals, and lubricate the exposed parts to protect a bike from wet conditions. Regular cleaning and lubricating helps with protection, but try to stop the mud and salt from reaching the delicate parts of the bike in the first place.

The overall aim when protecting a bike in winter is to prevent water reaching non-exposed parts and stopping water from washing off the lubricant on exposed parts. Mudguard Headset Mech Seat post collar Pedal Chain Shielding exposed components Sealing the seat post collar Sealing the headset Keep water out of the point where the seat pin enters the frame.

Mark this junction and remove the pin. Pull a piece of narrow road bike inner tube over the frame. Insert the pin through the tube to the mark and tie-wrap the tube to secure it. Place a cover over the headset to provide protection. You can fit a protector to the headset without removing any components by simply joining up the velcro. Preparing for wet weather Fitting mudguards Fasten a mudguard to the seat pin and you will block much of the spray from the back wheel.

For the front wheel, fit a guard that clips on to the frame and is secured in place with tie-wraps. Full mudguards, which attach to the fork and rear drop-out, give almost full protection for on-road biking but get clogged up off-road.

Weatherproofing the transmission Cleaning and lubricating the chain Cleaning and lubricating mechs Lubricate and clean your chain as often as you do in summer and after every wet ride. Apply the same light lubricant that you use in the summer and then apply a heavier oil, which will not wash off as easily.

Only coat the rollers and insides of each link with heavier oil because it attracts more dirt. Dribble oil on to the pivots around which the front and rear mechs move. Use a heavier, wet oil rather than the oil you would normally apply during the summer. Every time you dribble oil like this, first flush out the old oil by dribbling some degreaser on to the pivots and letting it sink in for a few minutes. Cleaning and lubricating pedals Apply heavier, wet oil to lubricate the retention mechanism of clipless pedals after degreasing all the moving parts.

The heavier oil will not wash off as easily as dry oil. Regularly clean off old oil with degreaser and apply new oil in order to prevent the accumulation of grit and the consequent increase in pedal wear.

Bicycle Repair Manual - Chris Sidwells

Finetune and regularly service the system to ensure that the gear-shifters, chain, chainset, cassette, and mechs work together in perfect harmony. Cables are under constant tension and need to be replaced regularly and kept well lubricated.

They must also be inspected often and replaced if they show signs of wear. Shifters require only occasional lubrication of their inner workings. How they work An inner cable connects the gear-shifter to the mech, and allows the rider to change gear.

Gear-shifts made by a gear shifter cause the front mech to shift the chain from one chainring to another, or the rear mech to shift the chain from one sprocket to another.

Pulling the gear cable shifts the chain from a smaller to a larger chainring or sprocket; releasing the gear cable shifts the chain from a larger to a smaller chainring or sprocket. The left-hand shifter controls the front mech; the right-hand shifter controls the rear mech. Controlling the gears The cables and shifters on a bike allow the rider to effortlessly control the gear system.

When the shifter is pushed, the cable pulls the rear mech inwards, moving the chain from a smaller to a larger sprocket. When the shifter releases the cable tension, the springs on the rear mech pull the jockey wheels, and the chain, back to a smaller sprocket.

When the rider depresses a lever on the inner side of the lever hood, the cable is released and the mech moves back. On this Shimano gearshifter, the brake lever also acts as a shift lever.

When the rider pushes the brake lever inwards with the fingers, the control cable attached to it is pulled and a ratchet mechanism is lifted. A click of this mechanism equals one shift of the front or rear mech, which moves the chain across the chainring or sprockets.

The ratchet mechanism then holds the cable in its new position. Change them as a matter of course at least once a year, or more often if you are a heavy user. Lubrication reduces the effects of friction between the inner cable and the cable outer, and helps to keep out water and grit.

If the gears become difficult to shift to a different chainring or sprocket, the cable is probably dry and needs lubrication. Friction increases with cable length.

Cut cable outers as short as possible, but not so short that they constrict the cable or restrict the steering. If you are unsure how much cable outer to cut, look at the arc of the outers on other bikes see pp.

Replacing a Shimano gear cable Place the gear-shifter in the smallest sprocket for the rear shifter and the smallest chainring position for the front shifter. You also need to do this if you are replacing a brake cable. Pull the tape off slowly. Drop handlebar gear cables Pull the gear cable through pre-cut lengths of cable outer with the long-nosed pliers.

Then tighten the bolt with the Allen key. Put the rear shifter in the smallest sprocket and the front shifter in the smallest chainring. Remove the old cable from under the hood cover. Dribble oil into a cable outer, which should be cut to fit between the cable guide and the component. If it is cut too short, it constricts; if it is too long, it increases friction see pp. Keep the cable to the mech under tension as you clamp it. However, mountain bikes are often subjected to harsher conditions than road bikes, as they are often ridden through dirt and mud, so the cables must be replaced and lubricated more regularly.

Take special care if your mountain bike has cable disc brakes because they have longer lengths of cable outer and the cables require lubricating more often.

Make the outers long enough to allow the cable to travel freely inside. Straight handlebar gear cables Replacing a Grip Shift gear cable Push the cable into the hole until its end shows through the barrel adjuster on the outside of the shifter body. For the rear cable, put the shifter into the smallest sprocket. For the front cable, put the front shifter into the smallest chainring. Replacing a Dual Control gear cable 4 Thread the inner cable through each length of outer cable.

For a front mech, insert the cable into the clamp. Cut off any excess cable. The mech pivots and jockey wheels must be checked for wear and lubricated. The front mech must be properly aligned with the chainrings. How they work The front and rear mechs change the gears on a bike.

To change up a gear, the shifter is used to pull on the cable, which causes the front mech to push the chain from a smaller to a larger chainring or the rear mech to push the chain from a smaller to a larger sprocket. To change down a gear, the cable is released, causing the springs in both mechs to move the chain to a smaller chainring or sprocket.

Each mech moves around a pivot point. High and low adjusting screws ensure that the mechs do not push the chain beyond the largest chainring or sprocket, or pull it beyond the smallest. Once its travel is set up, and provided the cable tension is sufficient, the mech will make a single, clean gear-shift for every click of the shifter. They move in the same plane as the chain and are spring-loaded to preserve the tension in the chain.

Two mech plates enable the jockey wheels to change gear upwards, while the plate spring enables the jockey wheels to change gear downwards.

Mech plate Transfers cable pull to the jockey wheels Plate spring Pulls the mech back as cable is released High and low adjusters Limit the travel of the mech Cable clamp Attaches the cable to the mech plates Cable Pulls the mech plates Jockey wheel spring Preserves the tension in the chain Jockey wheel Pulls and pushes the chain Jockey wheel cage Holds the jockey wheels Working with the shifters The front and rear mechs work in harmony with the shifters to provide easy, quick, and accurate gear-shifts whenever the rider needs them.

When the cable is released, the plate spring moves the chain back to a smaller sprocket. Large sprocket The chain is moved to the largest sprocket by the pull of the cable. Small sprocket The chain is returned to the smallest sprocket by the plate spring. This moves the chain from a smaller to a larger chainring. There are two main kinds: There are two important maintenance jobs for a front mech: You should also clean the mech regularly to prevent the build-up of dirt, which interferes with the way it works and will quickly wear it out.

Correct shifts depend on the front mech travelling a certain distance per shift. High and low adjusting screws on the mech will control this travel. Note the distance by which the lower edge of its outer side clears the largest chainring.

This should be 2mm. If it is more or less, undo the framefixing clamp and raise or lower the front mech. Front mech Undo the cablefixing clamp until the cable becomes free. Use degreaser, and then wash and dry the whole area. Occasionally, you may find that the chain does not quite move on to the next sprocket when you make a single shift, or else it skips a sprocket in an overshift.

In either case, the rear mech needs adjusting. You will also need to follow the steps in this sequence whenever you fit a new cable see pp. To ensure that the rear mech works faultlessly, pay particular attention to its jockey wheels because this is where oil and dirt can accumulate. Degrease and scrub them every time you clean your bike see pp. Whenever you lubricate the jockey wheels or the rear mech pivots, make sure that you wipe off any excess oil.

Shift the chain on to the biggest chainring and smallest sprocket, then undo the cable-fixing clamp so that the cable hangs free. If the rear mech does not shift all the way on to the next biggest sprocket, screw out the barrel adjuster until it does. If the mech over-shifts and skips a sprocket, screw in the barrel adjuster until it stops. Prevent the jockey wheels from making contact with the bigger sprockets by screwing in the adjuster that butts on to the rear mech hanger on the frame drop-out.

Remember to make this adjustment if you fit a block or cassette with bigger sprockets than usual. They require little routine maintenance and, since they are sealed, most hub-gear systems do not need to be lubricated regularly.

The control cables must still be inspected regularly and replaced if they are worn. How they work All hub gears work according to the same basic principle.

A system of internal cogs make the hub casing, and therefore the rear wheel, turn at a different speed to a single, external sprocket that is driven by the pedals via the chain. The sprocket is connected to the cogs by a driver unit and the cogs rotate the hub casing at different speeds.

Spokes attach the casing to the rim, thereby revolving the rear wheel. A shifter on the handlebar operates a mechanism attached to the hub.

This mechanism causes various combinations of different-sized cogs within the hub to engage with a ring gear, which drives the hub casing. Each combination gives a different gear ratio, and the number of gears depends on the number of cogs within the hub. This triggers a mechanism within the driver unit to move two carrier units containing cogs.

Different cogs are brought into contact with the ring gears. When the cable is released, the spring-loaded carrier units move the cogs back to a different combination. This is usually stamped on the hub and the number of gears is indicated on the shifter. The hub-gear model illustrated in the steps of this sequence is the Shimano Nexus 7-speed gear, which is operated by a twist grip shifter.

Alternatively, bikes may be equipped with SRAM hub gears, as well as those made by other manufacturers, that are operated by thumbshifters. Some older bikes have Sturmey Archer 3-speed gears. Although they all work on the same principle, the methods used to change a cable are subtly different. Put the shifter into first gear.

At this point, there is no tension on the cable, so it is the starting point for fitting a new cable. If the cable is broken, the hub gear will have automatically returned to first gear, so move the shifter there to line up the system. Hub gear I 2 Remove the rear wheel see pp. Undo the clamp to remove it from the old cable.

Dribble a little oil inside the outer and then push the new cable through the outer. Return the wheel to the bike by placing the axle in the rear drop-outs and pulling backwards on the wheel so that there is tension on the chain. Do not pull so hard that the chain becomes tight. If there is a problem, the hub gear may need adjusting see pp.

You will need to remove the satellite to clean it and this means removing the rear wheel. On other occasions, you might find that the shift has lost some of its smoothness. In this case, the cable has probably stretched so that the shifter is out of phase with the gear mechanism. To remedy this problem, use the barrel adjuster on the shifter to take up any slack in the cable. Every time the wheel is removed and put back on to your bike, run through the gears and check that they are shifting correctly.

If they are not, follow the last two steps of this sequence in order to make sure that the gears are running smoothly. Finally, the hub-gear system has clear markings — look for the red dots and the yellow dots and triangles — to help you to set up the gears. If a bike is fitted with a Sturmey Archer 3-speed hub gear, it may occasionally shift to second gear, but without any drive.

When this happens, put the shifter into the third gear position and look at the cable where it runs along the chainstay. The cable will be slack so that it sags. Undo the cable-clamp bolt near to the hub-gear unit and pull the cable through the clamp until it runs in a straight line.

Re-clamp the bolt and the gears will shift perfectly. Remove the rear wheel by undoing and removing both its axle bolts see pp. The satellite is locked on to the hub by a lockring. Turn the lockring by hand until its yellow dot lines up with the one on the satellite.

Line up its triangles with those on the axle. The satellite is now locked in place. Hub gear II Lift the satellite from the hub body, noting the relative positions of the two yellow triangles that are marked on it. Let this drain out and spray light oil into the satellite. Tilt the bike so that you can see the underside of the hub gear. Look for the two red dots on the gear mechanism. One is marked on the satellite and one on the lockring. Both dots are marked on the underside of the gear where the cable runs.

In fourth gear, these two dots should line up. If they do not, screw the barrel adjuster in or out until the dots line up. When they do line up, all the gear-shifts will be perfect. The parts are in continual contact, and the motion of pedalling inevitably leads to wear.

Bicycle Repair & Maintenance

No matter how well you look after each part, they will eventually need removing and replacing. The pedals drive the chainset and, via the chain, turn a sprocket attached to the hub of the rear wheel, which in turn rotates the wheel. Bikes with derailleur gears use mechs to shift the chain on to different-sized sprockets and chainrings, which make up the cassette and chainset. Each combination of chainring and sprocket provides a different gear ratio, giving up to 27 different gears that can be used to tackle anything from steep climbs to gentle flats.

It consists of sprockets that slide on to the cassette body, which is bolted on to the hub. The cassette body houses the freewheel, which allows the wheel to turn when the cassette is stationary. To transfer power efficiently the chain must be strong, but flexible enough to fit securely around the teeth of the chainrings and sprockets. To achieve this, a series of links articulate around joining pins, which are surrounded by revolving metal barrels. Rear wheel Driven by the sprockets Barrel Sits between teeth of chainrings and sprockets Joining pin Connects inner and outer links Outer link Shaped to allow quick gear shifts Inner link Rotates around the barrel Chainset Powered by pedalling Lightweight components The chain, cassette, and chainset are lightweight items that use the latest design and construction techniques to maximize strength and durability while maintaining an aerodynamic profile.

All chains eventually wear out, even if you clean and lubricate them properly. A worn chain, as well as being inefficient, will quickly wear out other transmission parts, and so prove expensive.

To determine how much a chain has become worn, either use a specialist gauge from a bike shop or measure the length of 24 links. If the length is greater than mm 12in , the chain is worn. New chains on derailleur gear systems are linked with a joining pin that comes with the chain.

You will need a link extractor tool to make this join. The thicker chains of hub gears, BMX bikes, and some fixed-gear bikes are joined by split links. Leave an inner link so that the two ends can be joined together. Chains Joining a split-link chain Thread a new chain through the jockey wheels and around the biggest chainring and smallest sprocket.

Join the chain by pressing the side of the split link with the pins fixed in its plate through the two inner-link ends of the chain. This establishes the length of chain you need. Push the split pin into the grooves of the split-link pins. These are sticking through the outer plate that you have just fitted. Their internal mechanisms — the freehub body of a cassette and the block in a freewheel — will eventually wear out and need replacing. The sprockets on both can also wear. These parts will also need to be removed whenever you replace a broken spoke on the drive side of the rear wheel.

The tools for removing a freewheel and a cassette depend on the manufacturer of the part that is fitted to the bike. However, if you are in any doubt about which tool you need, take the wheel to the shop when downloading a remover tool. Cassette and freewheel 2 Wrap the chain whip around a sprocket, and place the spanner on the remover. This holds the cassette, while the remover unlocks the lockring. On many cassettes, the remaining sprockets come off in one piece.

If they do not, you must put individual sprockets back in a certain way. Failure to do so will affect the precision of gear shifts. Usually, the sprockets are marked, so that lining up these marks ensures the correct sprocket orientation. Check the integral freewheel mechanism, which is independent of the hub.

Replace it with a new block if it is worn. Chainsets are attached in one of four ways. Those held in place by a hexagonal bolt can be removed with a chainset socket spanner see Step 1. Chainsets with a selfremoving Allen bolt can be detached with an 8mm Allen key see Step 2. Versions with a standard Allen bolt can be detached with the relevant Allen key see Step 3. Those on a hollow-axle bottom bracket can be removed by reversing the steps on pp.

When refitting a chainset, keep grease or oil from touching the axle. The chainset must be dry when fitted to the axle or it will work loose. After refitting, go for a short ride and then try the axle bolt again. If it is slightly loose, you should tighten it. Normal socket spanners are often too thick to fit into the space where the bolt is located.

Work from below the chainset so that if your hand or the spanner slips, the chainring teeth will not injure you. Make sure that the washer beneath the bolt has also been removed. When the extractor is fully in, turn its handle clockwise to pull off the chainset. Chainsets Unscrew a self-removing Allen bolt with an 8mm Allen key. These kinds of bolt extract the chainset as you unscrew them.

Use a long-handled Allen key if there is an Allen bolt holding the chainset on your bike. Usually, an 8mm key is the size required. Remove the chainring with a 5mm Allen key on one side and a chainring bolt peg spanner to hold the bolt on the other. You can do this without taking the chainset off the axle, but you must remove it if you are working on the inner rings of some triple chainsets. Standard chainring bolts are made from steel. Be especially careful not to over-tighten aluminium or titanium bolts.

Both use sealed bearings, which can wear out over time. If this happens on the cartridge version, replace the whole unit, but on a hollow-axle type you only need to replace the bearings.

Each type of bracket consists of an axle, two bearings, and two threaded cups called either the free cup and fixed cup, or the non-drive and drive-side cup. With the cartridge type, both cranks bolt onto the axle, but with the hollow-axle type, the driveside crank is fixed to the axle and only the non-drive side crank can be bolted on.

A third type of bottom bracket, the BMX bracket, has a threaded axle — the bracket is held in place by a locknut that screws on to the thread on the non-drive side of the axle. Providing strength The axle and bearings of the bottom bracket need to be both strong and reliable enough to bear the weight and power of the rider.

The cartridge bearings are located close to each end of the bottom-bracket axle. A tubular sleeve fits over the two bearings, filling the space between them. The fixed and free cups fit over this sleeve to create a totally sealed unit. The non-drive side crank slides onto the axle and is secured by two pinch bolts.

The crank cap bolt inserts into the end of the axle to hold the crank against the bearing, ensuring that there is no play, rather like the stem cap bolt on a threadless headset p. Their bearings are sealed from the elements — even from the water you use for hosing or pressure-washing your bike, provided that you turn the pedals forwards during the wash. When the bearings do eventually wear out you will have to replace the whole unit.

The remover tools for this job are specific to each particular bottom bracket, so check which make is fitted to your bike before downloading the tools. If you are planning a replacement, there are three types of bottom bracket axle to choose: The type used in the steps in this sequence is square-tapered; the type shown below is Octalink. Finally, if you are having any problems installing a bottom bracket on your bike, ask the experts at a bike shop to help you.

Installing a cartridge bottom bracket 1 Put the bike on a workstand and remove the chainset see pp.

You need to do this because different chainsets are designed to work with different axle lengths. The non-drive threads are sometimes referred to as the free-cup and the drive-side threads are known as the fixed cup.

Do not grease the drive side of a bottom bracket with Italian threads. This width determines the width of the bracket unit you need to download. Turn it anticlockwise if your bike has an Italianthreaded bottom bracket marked 36 x 1.

Insert the bottom bracket from the drive fixed-cup side using the remover tool. Fit the teeth of the tool into the indentations of the bottom bracket see enlargement. Use the remover to screw it in a few turns. Fully tighten the drive side, then the non-drive side. The bearings on which the axle runs screw onto the outside of the bottom bracket shell, which allows a large diameter axle to be used that is hollow, light, and stronger than other axles.

Since the bearings are further apart than on other types of bottom bracket, they encounter less torque, which increases their lifespan. However, they will still eventually wear and have to be replaced, so you will need to know how to remove and replace them.

You will also need to follow these steps if you want to upgrade to this system. The faces of the bottom bracket shell must be flat and parallel. This requires specialist equipment, so get the frame checked at a bike shop. Parts of a hollow-axle bottom bracket Chainring Axle Combined drive-side cup and sleeve Left-hand crank Spacers Non-drive side cup 4 Pinch bolt Crank cap bolt Push the left-hand crank onto the nondrive side of the axle.

To do this, match the wide notch on the axle with the wide tooth on the crank. Put a little grease on the axle before you fit the crank. Hollow-axle bottom bracket 2 Screw the cups into the frame as far as you can with your fingers inset. Hold the drive side right-hand crank and push the axle through the hole in the centre of the drive-side cup. If this happens, give the centre of the crank a sharp tap with a plastic mallet.

Tighten them in sequence by screwing in the first a little, then screwing in the other by the same amount. Repeat until both bolts are tight, but do not use excessive force. Rotate the cranks and if the axle is stiff, loosen the crank cap bolt a little. The biggest difference between this kind of BMX bracket and normal bottom brackets is that the threads securing it in the frame are on the axle and not inside the bottombracket shell.

The axle has a cup and cone bearing system, a little like an open-bearing hub see pp. The drive-side cone, chainring, and axle are made in one piece, and the cranks bolt on to them.