Innholdsfortegnelse for Bike Maintenance Tips, Tricks & Techniques 3rd Edition i Bike Maintenance Tips, Tricks & Techniques

• Remove the punctured wheel. The first thing to do is locate the hole. If you’re running sealant, it should be obvious as the fluid will have leaked from the hole. If you’re not, then first look for any holes in the tread or rips in the tyre’s sidewall. If this doesn’t reveal the culprit, then pump the tyre up if it’s lost all its air and pass it past your face – you should hear air hissing when the hole is closest to your ear, may see bubbles if the ground is wet or feel the air cooling your cheek. Once you’ve found the hole, mark it or make a note of where it is in relation to any labels on the tyre or rim. • Remove one side…

The most common problem, which applies to all types of crank, is the crank bolts working loose so that the crank then begins to move on the axle. On a square taper, ISIS or Octalink crank, this can result in the crank bolt becoming so loose it actually falls out, allowing the crank to fall off completely. If you’re using clipless pedals you’ll find yourself with one foot attached to the bike and another with a useless crank and pedal dangling off the end! On a two-piece crank, you’re less likely to lose the crank completely as the preload cap will hold it in place but you can damage the shallow splines inside the crank if you stamp down on the pedals whilst the pinch bolts are loose. Both situations…

When splitting and rejoining a Shimano chain, the rivet must be pushed all the way out, then replaced with a special Shimano joining link. The rivets are different lengths to match the different chain widths used by eight- and ninespeed systems, so make sure to choose the correct replacement: the longer eight-speed rivets are grey, the shorter nine-speed version is silver. The replacement rivet is twice as long as the original rivets and has a groove in the middle. The first section is a guide to locate the rivet correctly in the chain and must be broken off once the second part of the rivet has been driven home with the chain tool. This means you need pliers to snap the guide off, as well as a replacement rivet. The…

Even if you don’t wear out blocks very quickly, you should still change them periodically as they harden with time and don’t work as well. Every couple of years should do. In between full changes, check on the condition of the pad and improve it. This is easiest to do with the wheels removed. Release the brakes and remove the wheel. Look at the condition of the pad. It should be flat and even, without visible contamination. If you can see flecks of metal, use a sharp knife and carefully pick them out. If the pad has been sitting too low or at an angle, it will wear unevenly, leaving a lip that gets caught under the rim and prevents the brakes from letting go properly. This is a waste…

Rim design is subject to two competing demands. When you’re trying to go faster, it helps to have rims that are as light as possible. Your wheels are spinning around as well as along, so saving weight on them makes the bike feel substantially faster than saving the same weight on a static part of your bike like the handlebars. So ideally, the rims should be as thin as possible so that they don’t weigh much. Light wheels mean it’s much easier to make your bike accelerate, as well as to make it change direction when you’re moving fast. If this doesn’t make sense to you, take a wheel off your bike. Hold each end of the axle and move the whole wheel up and down. Then spin the wheel…

However, the blocks must be close enough so that when you pull the lever the blocks bring the wheel to a stop when the brake lever is somewhere near the middle of its travel. You shouldn’t be able to pull the brake-lever back far enough to touch the handlebars. This means you haven’t got enough power to bring the bike safely to a stop. Some prefer a little bit of movement of the levers before the brake blocks bite as it means they can get a proper grip on the lever. This adjustment will only work if the wheels are aligned centrally in the frame. Check that the gap between the tyre and the frame or fork is the same on either side of the wheel and realign the wheel…

There are other circumstances in which you might want to replace the first section of outer casing. You may want to raise the bars and find that the casing isn’t long enough to do so without forcing it around tight bends. You may also have found damaged or kinked spots in the casing. Either way you’ll need to get some fresh bar tape before you start. It is possible to reuse the old stuff, but it’s sticky-backed so doesn’t often come off without tearing and tends to refuse to lie flat when you wind it back on again. Treat yourself to new tape – it makes your bike look much smarter too. Best results come from changing the whole lot at once. Peel off the old stuff gently. You’re trying…

There are two parts to a disc brake: the calliper, which bolts onto specific mounts on your frame or fork and the rotor (or disc), which fits directly onto the hub of your wheel. Disc brakes have two distinct advantages over rim brakes. Firstly, they don’t wear out your wheel by abrading the rim every time you brake. Secondly, the harder, cleaner surface of the rotor makes for powerful braking. Mechanical disc brakes are easier to work on because they use standard V-brake levers and cables. Hydraulic brakes are more powerful and more resilient to wet, muddy conditions. Disc brakes are available to suit every purpose and budget out there, all the way from super lightweight XC bling to workhorse heavyweights. Braking power Braking power is dependent on two things:…

Calliper position is easy to adjust with the Post Mount system but it’s important to ensure that the pads are parallel with the rotor before tightening the bolts that hold the calliper in place. It’s remarkably easy to bolt the calliper on at a slight angle, so that one pad touches the rotor at the top and the other at the bottom. Even if this doesn’t make the brake noisy and draggy, it will make it feel mushy rather than sharp and is to be avoided. Step 1: If you are reusing the calliper bolts, place a spot of thread-locking compound on the thread. New bolts should come with this already applied. Fit a washer to each bolt if one’s not already on there, then push the bolts through the…

The position of the outer pad is controlled by the cable tension, while the inner pad remains stationary. When you pull the brake lever, the outer pad is pushed onto the rotor, which flexes sideways against the stationary pad and becomes trapped between the two. The distance between the rotor and the pads is adjusted separately on each side. The brake lever barrel-adjuster is used to set the gap between the outer pad and the outer surface of the rotor, while a bolt on the back of the brake calliper allows you to finetune the gap between the stationary pad and the inner rotor surface. The gap on either side is critical – too much space, and you’ll have to pull the brake lever all the way back to the…

Bedding in brand new brake pads is vital. If you skip this task you’ll find that you suffer both poor braking and vanishing disc pads. New pads need to be ’cooked’ to remove chemical residues left over from manufacture and harden the braking surface. You do this by braking to heat up the pad, then allowing it to cool, and repeating until the braking performance improves, so find yourself somewhere that you can ride safely without having particularly sharp brakes (ie not a busy A-road or a steep descent). Then ride along slowly, before braking until you’ve nearly come to halt. Repeat this process until the braking performance improves; it’s not unusual for it to take ten to twenty cycles. Be aware that the braking performance will improve suddenly so…

Joining the chain gang If you are disciplined about measuring your chain carefully and regularly with a chain-measuring device, you can replace just the chain before it has a chance to wear the other components of your drivetrain. This tool will tell you when you have reached this point. If you are attentive, you’ll find it the cheapest option in the long term If you allow the chain to wear beyond this point, you will have to replace both the chain and the cassette at the same time. The old chain will have damaged the teeth on the cassette, so the new chain will be unable to mesh with it neatly. The consequence of changing the chain without changing the sprockets is that the new chain will slip over the…

To locate the stiff link, lean your bike up against a wall with the chain in the big chainring at the front and the small sprocket at the back. Pedal slowly backward with your right hand and watch the chain as it feeds out of the bottom of the cassette, around the jockey wheels, and off the bottom of the bottom jockey. You see the bottom jockey wheel skip forward as the stiff link passes through the rear derailleur. Keep pedalling backward, and allow this section to pass through your fingers to pin down the stiff link. Step 1: Once you’ve found the stiff link, look at it carefully from above. You may find that one side of the rivet pokes out of the side of the chain more than…

The standard fitting for attaching sprockets to the back wheel is the cassette. The cassette fits over the ratcheting mechanism, the freehub. This is bolted onto the hub, with the bearing at the outboard end. The freehub allows the wheel to go round on its own without pushing the pedals, that is to freewheel. The freehub makes a clicking noise when you freewheel. Cassettes and freehubs are made by different manufacturers, but all adhere to the standard Shimano-fitting pattern. The outer shell of the freehub is splined, a fancy way of saying it has grooves in it. The cassette has a matching set of grooves to slide over the freehub. Everything is kept in place with a lockring, that screws into the outer end of the freehub. The first common…

Either of these contingencies will damage your bike, cutting through the spokes where they join your rear hub or taking chunks out of your frame beside the cassette. The chain will get firmly wedged too, so the chances of you falling off and hurting yourself are quite high. Only the heads of the end-stops screws are visible, the shafts of the screws are hidden inside the body of the derailleur. The derailleur is designed so that, at either end of it, the tips of the end-stop screws come into contact with tabs moulded into the pivoting part of the derailleur. Screwing the end-stop screws further into the body of the derailleur means that the ends of the screws hit the tabs sooner, limiting the movement of the derailleur and preventing…

If your shifting is still sluggish after you’ve adjusted the endstop screws and the cable tension, then it’s time to treat your rear derailleur to a little clean and re-lubrication. The separate sections of the derailleur need to be able to move freely, so that your shifting is crisp. The pivots that connect the parts work best if they’re not jammed up with dirt and have a little oil to lubricate them. The first step is to clean your rear derailleur. This is easiest with the back wheel removed, so you can get to everything. Wipe down the outside, then use a little brush to get mud and dirt out from inside the mechanism. You don’t need to carry that muck around with you. You need to move the derailleur…

Remove old cable and casing, cutting off the old cable about 15cm (6 inches) before it enters the shifter. You’ll need to shift into a particular gear to expose the head of the cable. When you look at your gear indicators, one may be a different colour than the others, or one of the numbers may have a circle drawn around it. If all the numbers look the same, shift into the highest number on the right-hand shifter (8 or 9) and into 1 on the left-hand side. Step 1: Pull gently on the cable as it enters the shifter through the barrel-adjuster and shift into the correct gear. Remove the escape hatch or slide it to one side (sometimes this needs a little help from a screwdriver or pliers)…

Disc brake callipers: (aka disc brake units) These are bolted to mounts on your frame and fork. Pulling the brake lever at the handlebar clamps the disc rotor between thin, metalbacked brake pads. Powerful and resilient, they can seem daunting to service thanks to the hydraulic system but they´re actually very straightforward. Mechanical versions use cables and V-brake levers rather than an oil-filled hose. Rear derailleur: This moves the chain step by step across the cassette sprockets. Differentsized sprockets give you different gear ratios, so that you can pedal at a constant rate over a range of different speeds. The movement of the rear derailleur is controlled by a cable on the shifter on the right-hand side of the handlebar. Correct adjustment gives you slick shifting and ensures maximum life…

There are ways to reduce the number of punctures you get. Occasionally you pick up a sharp object that cuts straight through tyre and tube and causes a flat, but often objects take a while to work their way through the casing of the tyre. Before you set out, check both tyres: raise each wheel off the ground in turn, spin each slowly and pick out foreign objects. Maximum and minimum pressures are printed or stamped on the tyre sidewall. Make sure the tyre is inflated to at least the minimum suggested pressure to reduce the chance of snakebite flats (caused when pressure from, say, a rock edge, squeezes two symmetrical holes in the tube against the sides of the rim). If you like running at very low pressure, choose…

Once you get home, patch the tyre. Tyres are expensive, and patches work, so it’s worth the effort. Finding the hole can be the tricky bit! Pump as much air as you can into the tyre and listen for hissing from the hole. Look carefully for a thorn or other spiky object sticking out of the carcass; you may also spot sealant bubbling out of the hole. Sometimes the hole is tiny and hard to locate, and you have to submerge the inflated wheel in water to look for the bubbles. This is much more awkward than doing the same process with a tube! Once you’ve located the hole, mark it carefully or you will lose the place! I usually draw a circle in ballpoint around the hole, then draw…

The combination of angle and stress is too much for the fragile, put-upon chain and it gives way, leaving you suffering a sudden loss of drive and balance and possibly vaulting over the bars if you were stamping hard on the pedals at the time, too. Learn how to use your gears correctly and you’ll avoid unnecessary problems; similarly, keep your drivechain in good condition, as old, worn and neglected chains are more likely to let you down under pressure. For most chain problems, you’ll need a chain tool. These can be annoying to carry as they only do one job but it’s extremely hard to botch a chain repair using anything else. Several manufacturers, like Park and Topeak, make good chain tools that also fold so invest in a…

Twisted links The gaps between the chain plates are only just big enough to fit a sprocket or chainring tooth into, so once a link is twisted it usually rides up over the tops of the teeth rather than dropping into the valley, causing your chain to slip under pressure. Alternatively, if the twisted link does mesh successfully onto a chainring tooth, it can get stuck and be sucked around the back of the chainring, getting jammed between the chainstay and the chainring. As well as being annoying, this damages the chainring and chainstay. Even after you’ve worked out that you have a twisted link, it can be tricky to spot. The best place to see one from is behind the bike. Get someone else to hold the bike upright…

V-brakes ousted cantilevers because they are more powerful, as well as being easier to adjust. However, there has always been a trade-off in terms of pad wear – cantilever pads last much longer. V-brakes stop you faster because the way they are designed pushes them onto the rim harder than cantilevers, wearing out both the rim and brake blocks faster. So, enjoy the powerful braking but remember that as a direct consequence you are going to have to learn to inspect brake blocks frequently for wear and replace them. Depending on where and how you ride, you can wear out brake blocks at the rate of a set per day, and through a rim in a matter of months. Regular maintenance Keeping blocks and rims clean will make a huge…

The key is to set up the brake units so that they’re parallel and vertical before fitting the brake blocks into the units. Most new brake blocks come with a new set of curved washers but occasionally you’ll have to reuse the old ones. It’s a good idea to clean your rims at the same time so that the new brake surfaces can get maximum grip. Step 1: Undo and remove Allen key nut on the end of the old brake block stud, then wriggle out the old block and its curved washers. The new brake block comes with fresh washers, but keep old ones as spares. Now look at the position of the brake units. They should be parallel and vertical (A). Get the position of the units right…

Cables generally come in either standard or fancy versions. The luxury versions tend to be either lined or protected by a sheath that runs from shifter to brake. Luxury cables can make a significant difference if you ride in very muddy environments, as they stop grit from creeping into the gap between cable and outer casing. However, they are generally much more expensive. All cables come with comprehensive instructions though, so we’ll stick to standard cables here. You can either buy brake-cable sets in a pack, with cable, outer casing and ferrules – Shimano make a good value pack – or you can buy the parts separately. Ferrules are the metal caps that the end of your outer casing sits in. Either way, you’ll need a decent pair of cable-cutters…

Hold the eye bolt still using a 5mm Allen key in the head of the eye bolt, and undo the nut at the back of the unit – usually with a 10mm spanner. You don’t need to take the nut off, just loosen it enough to pull the old brake block out of the hole in the eye bolt. Feed the stub of the new brake block back through the hole in the eye bolt so that the brake block faces the rim. Most brake blocks will fit either way around, but if there are any arrows printed on the block, point these forward. If one end of the brake block is shorter than the other, this goes at the front. Step 1: Tighten the nut just enough so that…

Readjusting your cable angle will help you stop more quickly, but you may have to readjust your brake block positions. If you’re fitting new cables and blocks, adjust the cable angle first, then fit the brake blocks to match. The brake unit is attached to the frame by a single fixing bolt so that the brake unit can rotate around the bolt. The cable attachment points on the tops of the brake units move in a circle around the fixing bolts. This means the cable must be set up to pull the brake units around this circle – there’s no point in pulling them in any other direction. This brake cable angle is best estimated by setting the sections of cable that connect the brake units so that they’re at…

The calliper mechanism means you can’t apply as much force to the block to stop you as you can with a V-brake, so it’s worth investing in good-quality brake blocks and replacing them when they’re worn. Good makes include Aztec, Shimano and Kool-Stop. Of the three types of rim brake, calliper blocks are the easiest to change. Give your rims a good clean at the same time, and check them for wear. There are only two types of fitting for brake pads – most common are 4 or 5mm Allen keys, but some need a 10mm Allen key. You may decide when you’ve got the old brake block off that it will survive a little longer – if so, clean it up carefully. Use a sharp knife to pick out…

Like your gears, your brakes are operated by a combination of a cable and a spring. Cables are great for transmitting a signal through all the curves from your handlebars to your brakes and they’re light and strong, but they can only pull, not push. Once you’ve used the cable to pull your brake blocks onto the rim, you release the brake-lever and rely on a spring in the calliper to push the blocks back off the rim so that you can ride and the blocks are back in their original position. However, your hands are generally much stronger than the little coil of wire that does the springing-back job. The effect of this is that, once your calliper pivots start to get all clogged up and sticky, you will…

There are now several different axle standards, each with their own benefits. Quick-release hubs are still very common despite evidence that they lack the clamping power to resist the forces created by powerful brakes with large rotors and at the speeds which longer travel bikes allow riders to attain. If you’re running quick-release skewers with disc brakes, use robust, good-quality skewers. Shimano and Mavic are both excellent – and ensure that the mechanism is clean and well lubricated. ’Lawyer tabs’ are now standard on quick release forks, and though the little protruding lips below the drop-out mean you have to undo your quick release that much further to get the wheel in and out, they make it harder for the wheel to be accidentally removed if the quick release is…

Make sure you get the right pad for the brake; the fittings and shapes vary between makes, and between models from the same make. Take the old ones along to your bike shop for comparison if you’re not sure. Even if you know the make, the shape will vary from model to model and from year to year. After fitting, new pads need to be bedded in – they don’t work properly until you’ve braked a few times. Once you’ve got the new pads in, find somewhere you can ride the bike safely with limited braking power. Ride along slowly, haul on the brakes and bring the bike to a halt. Repeat at increasing speeds, until you’re satisfied. This may take 10 or 20 repetitions. The pads on mechanical brakes…

There are two types of fluid that are commonly used in mountain bike disc brakes and you MUST use the right one for your brake – using the wrong one will damage seals throughout the system irreparably. DOT fluid has a higher boiling point and expands less at high temperatures, whilst mineral oil is easier to work with, less corrosive and less environmentally damaging. There isn’t a significant performance difference between the two when used in mountain bike brakes, just don’t confuse them. Both types will eventually absorb moisture from the air and become less effective, so buy small amounts and keep them sealed, disposing of leftover half-bottles responsibly if they’re been hanging around for a while. Wear rubber gloves to protect yourself when using both types of fluid, as…

Fit the new brakes to your bike first and go for a ride, though – tape the hoses to your frame if you have closed cable guides. This means that you will at least know how the brakes are supposed to feel before you tackle the task of shortening them, and so will be able to recognise whether or not any air has got into the system in the brief period that you have the hose loose from the lever. All brake hoses can be cut to length, though braided ones require some care and effort. A little bit of a graceful curve is fine and you need to make sure that hoses are long enough to allow the bars to turn fully without being restricted by the hose. It’s…

Hope Minis are my favourite brakes, and are likely to be around a while. They work very well, weigh very little, look pretty and are made by the same nice people from the north of England who answer the phone in a reassuring Lancashire accent to respond to your technical questions with useful, friendly answers. Hopefully you won’t need to do anything to yours for years after fitting them except change the pads. The Hope Minis use DOT 5.1 fluid, which you can buy in small bottles from car spares shops. Don’t buy a large bottle because the fluid absorbs water and becomes ineffective once the seal has been broken. Step 1: Remove the wheel. The brake pads must be removed to avoid contamination – remove the spring clip on…

For example, if you’re fitting a new rear derailleur, undo the bolts that hold on the jockey wheels, thread the chain around the jockey wheels, and reassemble them with the chain inside the derailleur, rather than splitting the chain. Make sure you tighten both jockey wheel bolts securely – the top one, particularly, is prone to rattling loose. For the front derailleur, remove the bolt at the back of the cage, slide the chain into the cage and refit the bolt. If you do have to split the chain, you’ll need a chain tool. This is designed to support two adjacent chain plates while you push out the pin between them. It is important to do this carefully, as they may create a weak point and break later if you…

Notches, splines and dogs The most difficult thing here is choosing the correct tool. When freewheels were standard, there were a plethora of different designs, involving splines and dogs. Luckily, there are now fewer designs, and the only ones you’re likely to come across commonly are the Shimano splined freewheel and the SunTour 4dog freewheel. (A splined tool has ridges that fit into matching ridges in the component running along the tool. A dogged tool has pegs, called ’dogs’, that fit into matching notches on the component.) Additional advice on freewheels Fit the wheel back on the bike and change into the lowest gear (largest back sprocket, smallest front chainring). It’s important to make sure that the freewheel is firmly screwed on. With the bike on the ground, turn the…

Adjusting your indexing: derailleur types – Standard and rapid rise Before you start adjusting, use the following method to check whether you have a standard derailleur (by far the most common on all bikes) or a rapid-rise derailleur. Change into one of the middle cassette sprockets. Take hold of any exposed part of the derailleur cable where it passes along the top-tube or down-tube of your bike, and pull the cable gently away from the frame. Watch the derailleur: • If it moves towards a lower gear (larger sprocket), you have a standard derailleur – follow the instructions on page 116. • If the derailleur moves towards a higher gear (smaller sprocket) when you pull the cable, you have a rapid-rise derailleur (lownormal). These were introduced a few years ago,…

For example, in their XT and XTR mountain bike ranges, Shimano currently make three different versions (top normal, low normal and Shadow), with two different cage choices for each, making a total of six different options. Road bikes have fewer varieties. Most bikes are fitted with a ’top-normal’ rear derailleur. This simply means that increasing the cable tension makes the derailleur shift the chain onto a larger sprocket (lower gear), while releasing the cable tension allows the chain to drop back to a smaller sprocket (higher gear). Less common are ’low normal’ derailleurs, which used to be called ’Rapid Rise’. These work in reverse, so that increasing the cable tension makes the derailleur pull the chain onto a smaller sprocket, while releasing the cable tension means the chain climbs onto…

One of the most common problems to be routinely ignored is the alignment of the rear derailleur hanger (the part on the frame that the derailleur bolts onto). The gears are designed to work when the two jockey wheels hang vertically underneath the sprockets. This vertical alignment is the first casualty of a crash, but it’s often overlooked – you get up and brush yourself off, look at your bike and, if everything looks okay, you ride away. Bad things can happen next. If you’ve crashed and bent your derailleur inwards, the gears may still work, but everything has shipped inboard a little. Next time you stamp uphill in a low gear, you click the lever to find a bigger sprocket, but instead you dump the chain off the inside…

There are two separate screws, each controlling one end of the derailleur range. The ’low’ adjustment screw prevents the derailleur swinging too far towards the frame, dropping the chain into the gap between chainset and frame. The ’high’ adjustment screw prevents the derailleur from throwing the chain off the outside of the chainring. Before you start adjusting, work out which screw does what. They’ll have H and L marked on them, or a long line next to the H screw (representing the big chainring) and a short line next to the L screw. These indicators will helpfully be printed in black on a black background. Usually, on ’conventional’ front derailleurs (where the band that clamps the derailleur to the frame is higher than the derailleur cage), the H screw is…

There are two types of shifter. The first has two separate parts to each brake-lever. Swinging both parts inwards towards the centre of the bike pulls cable into the shifter; pushing just the part nearest the bars sideways releases cable from the shifter. Pushing this lever repeatedly inwards slackens the cable. The second kind has a single brake-lever. Swinging this sideways towards the centreline of the bike increases cable tension. There’s also a thumb button on the side of the brake-lever body. Pushing this repeatedly releases cable until you reach the ‘cable slack’ position. These instructions start after you’ve removed the old gear cable. Step 1: Test the shifter action. Pull the gear cable gently towards the centreline of the bike. Operate the two levers in either direction – you…

The exit point for the cable is hidden beneath the cowl of the shifter. To access it, you need to pull the lever right back towards the handlebar. The exit hole will be on the outside of the lever blade, directly opposite the point where the outer casing enters the lever. The cable can only be extracted when the gear shifter is set so that the cable is slack. There are two types of STi shifter. In the first, the brake-lever is in two parts. Swinging both inwards towards the centre of the bike makes the cable tighter; swinging just the back one towards the centreline loosens the cable. In the second, there is a single brake-lever, which you swing inwards to tighten the cable. A thumb button on the…

Delicate parts, which just need holding in place, come equipped with small bolts. The spanners that fit these bolts are short so that you don’t have enough leverage to overtighten the bolt. Parts that need to be clamped down firmly come with a big bolt that you can attach a nice hefty spanner to and lean on. This used to work well enough, but as riders we’re demanding lighter equipment all the time, so manufacturers are designing components with less room for error. For example, replacing steel bolts with aluminium ones will save weight, but aluminium bolts are far less forgiving of overtightening; once stressed, they can snap without warning. Overtightening bolts can also strip the thread that you’re bolting into. This is a common problem with aluminium parts. For…

Your first step is to inspect the tyre carefully. Look around the outside for thorns, shards of glass or sharp stones. If you can’t see anything from the outside, check the inside of the tyre too. The easiest way to locate the culprit is to feel around inside the tyre with your fingers, moving slowly and carefully to avoid cutting yourself. If you’re still unsure what caused the flat, pump air into the tube and locate the hole. You may be able to hear it rushing out of a big hole. Smaller holes can be harder to find – pass the tube slowly through your hands so that you can feel the air on your skin. You can put the tube in a bowl of water and watch for bubbles,…

Fixing punctures To repair a punctured tube, start by locating the hole. Pump up the tube to about twice the original diameter. You might be able to hear the air hissing out of the hole straight away, and locate the puncture that way. If not, lick the palm of your hand and move it along the tube, about a centimetre away; you’ll feel the cold air from the puncture on your hand. Roughen the area with the sandpaper from the patch kit; this helps the patch stick – and means you don’t lose the hole. Let all the air out of the tube again. Spread glue in a spiral out from the centre of the hole, making a glue patch that’s generously bigger than the patch. This next step is…

To find a stiff link, change into the smallest sprocket at the back and the largest chainring at the front. Lean the bike up against a wall, crouch beside it and pedal backwards slowly with your right hand. The chain heads backwards from the top of the front chainring, around the smallest sprocket, then around the front of the guide jockey and the back of the tension jockey. Then, it heads to the front chainring again. The chain is straight as it travels across the top, then bends around the sprocket. The links should be flexible enough to straighten out as they emerge from the bottom of the sprocket, then bend the other way to pass round the guide jockey. But a stiff link won’t straighten out as it drops…

The steps below make up a quick and regular check to keep your brakes in good running order and they give you warning when it’s time for a more serious overhaul. Each of the steps below includes relevant page numbers, so that if any of the checks show a problem with your braking system, you can sort it out straight away. Whatever you do, don’t set off on a ride with brakes that don’t work properly. Lift each wheel and spin it, to check the brakes don’t rub on the rims or the tyre as the wheel turns. Look at the gap between the brake block and the rim on each side of each brake. See pages 53-55 for more. You’ll need to disconnect the brake cable so that you…

All V-brake units are made to fit the same size and shape of brake pivot, so you can swap between makes and models without running into compatibility problems. New brake units are supplied with a set of new brake blocks. Once you take the price of these into consideration, a new set of brake units is a good-value upgrade. Servicing V-brake units Old brake units that are a bit tired can be revived with servicing. You’ll need to release the brakes, then disconnect the cable clamp bolt. Undo and remove the fixing bolts at the bottom of each unit, then pull the brake units off the brake pivots. You may need to wiggle and pull at the same time, especially if the brake pivots have become corroded. Use a small…

If your cables are gritty, rusty or kinked, they won’t release freely, leaving you with sluggish, dragging brakes. When cutting new lengths of outer casing, check that each section is long enough; for example, the section that joins the handlebars to the frame should be long enough so that the bars can turn freely, without kinking the casing. The casing for the front brake should make a smooth, graceful curve. Cut new lengths, neatly and squarely with good, sharp cutters. Don’t leave a ragged edge. If the lining gets squashed as you cut, prise it open with a sharp knife. Fit ferrules on each end of each section of casing. The final section of cable – connecting the cantilever units to the cable – is set up in two ways:…

There is not as much choice available in cantilever brakes as there used to be once upon a time. There are however still some very goodquality models are still made for cyclocross bikes; for example, Avid Shorties are light, strong and powerful, though some people say they squeal too much. Step 1: Pull the quick-release on your brake unit down and out to release it from the slot on the unit. If the slot in the brake unit has become squashed, use a thin screwdriver to carefully ease the slot apart so that the cable slides out without damage. Step 2: Cut off the cable end, undo the cable clamp bolt and release the cable from the units. Use this opportunity to check the condition of the cable, particularly where…

The back brake in particular has a long cable, and both cables are routed under the bar tape, so they’re forced around tight turns. Once the cables start to deteriorate, you’ll find that the levers become steadily harder to pull, and the brake blocks don’t spring easily back from the rims once you release the levers. Replacing the cable makes a massive difference If the outer casing is kinked or damaged, it should be replaced at the same time as the cable. Use the old sections to measure out new sections, taking care to cut the ends clean and square. New bits of casing need a ferrule at each end of each section. The exception is the last one, where the casing enters the calliper. There may not be room…

Always do one brake at a time – that way, you’ve always got a complete one to refer back to if you get stuck in the middle of reassembly. Take particular care to clean road grime away from around the return spring. There isn’t much of a gap between the spring and the calliper arms, so it doesn’t take much of a build-up of detritus to make everything feel sluggish. For the full spring clean effect on tired brakes, combine this service with a new pair of blocks and a new brake cable. Once you’ve got all your tools out, it doesn’t take much longer to do the whole lot at once, and you’ll feel the difference in increased braking control straight away. Fresh brake blocks are easier on your…

Mechanical disc brakes can be fiddly to adjust. The clearance between pads and rim must be small, without allowing the pads to rub on the rotor. A common source of confusion is that only the outer brake pad gets moved by the action of the cable, pushing the rotor against a stationary inner pad. This means that the two pads have to be adjusted in different ways. You will really benefit from a workstand for this task. If that’s not possible, press-gang a mate into lifting the wheel off the ground at opportune moments. Before you start adjusting, spin the wheel, look into the calliper slot and check how much clearance there is between rotor and pads. If the brake binds as you ride, one or both pads are rubbing…

The brake hoses supplied with new brakes are almost always longer than you need, so that they can fit all sizes and types of bike on the market. Trimming them down keeps the bike looking tidy and also reduces the chance of the hose getting caught on trailside foliage, which can cause you to crash and possibly damage the hose, leaving you stranded and brakeless. As with every cutting task, it’s better to measure twice and cut once than vice versa but if in doubt err on the side of caution, as whilst it’s easy to remove more from a hose, you won’t be able to lengthen one you’ve already cut! It’s best to use new olives every time you refit the hose – the old ones often become deformed…

Make sure that you replace the fluid with the same mineral oil; filling it with DOT fluid will damage the seals irreparably and you’ll end up with a very big repair bill. Shimano sell a dedicated bleed kit for their brakes which includes a single-use bottle of oil containing enough for one (careful) bleed. Conveniently, this means that there’s no leftover oil to sit around absorbing moisture from the atmosphere. Mineral oil changes colour as it goes ’off’, so if you haven’t bled the brake for some months and are starting to suffer poor braking, remove the top cap of the brake lever and check the fluid – if it’s lost its pink tint then you need to replace the oil. You’ll be pouring the fresh oil straight into the…

Imagine you no longer have a spangly bike with dozens of gears. Instead, you have a model with only two chainrings at the front, which you turn by pedalling, and two sprockets on the back, which push the back wheel around when they are turned. This leaves you with a 10-tooth and 20-tooth sprocket at the back, and a 20-tooth and a 40-tooth sprocket at the front. These combinations aren’t useful for cycling, but they make the math easier. Start with your chain running between the 40 at the front and the 10 at the back. Begin with one pedal crank pointing upwards, in line with the seat-tube. Turn the cranks round exactly once. Each link of the chain gets picked up in the valley between two teeth. Since there…

Shimano make a special replacement rivet that can be pressed back through the chain to rejoin it. Whenever you split the chain, the original rivet must be pushed out completely and discarded. This can be irritating, but the payoff is that Shimano chains are strong and change very slickly. One of the rivets on your chain is the original joining link that was fitted when the chain was put together. You mustn’t split the chain again at this link. You can identify it easily – most of the links have words printed around the rivet, saying ’Shimano’ and the code number of the chain. The original joining rivet has no words printed around it; avoid this one. Also avoid splitting the chain in the same place twice – any previously…

The important thing to remember during this procedure is always to start in the same place, with the cable tension at its slackest and the chain in the smallest sprocket. Otherwise, it’s easy to confuse yourself, matching up the third shifter click with the fourth sprocket, or whatever. You will either need a workstand, to keep the back wheel off the ground, or the assistance of a friend, to lift the bike up for you at the appropriate moment. Before you begin changing the cable tension, familiarize yourself with the action of your shifter. Follow the casing that emerges from the right-hand shifter to where it joins the top tube or down tube, emerging as bare cable. Hook your finger under the middle of this section of bare cable and…

Derailleur pivots will wear over time, causing sluggish shifting as the guide jockey struggles to respond to changes in cable tension. Take hold of the bottom of the derailleur cage and rock it sideways, towards and away from the back wheel. A bit of flex is fine, but if you can feel the cage knocking, replace the derailleur. This task is easiest when you have as much chain slack to play with as possible. That’s why you should change into the smallest sprocket at the back, while at the same time dropping the chain off the smallest sprocket at the front and into the gap between the chainset and the frame. Clip the end-cap off the cable. “A bit of flex is fine, but if you can feel the cage…

It’s also tricky to adjust gears because they behave differently under pressure. Gears that feel perfect when you’re trying them out in the garage can be disappointing when you try them out for real. Occasionally, the opposite situation occurs: you can’t get the gears to shift properly at all in the shop, then you go for a ride anyway and unexpectedly they feel fine. Adjust cable tension If you’re unhappy with the shifting, the most sensible place to start is with the cable tension adjustment. Click the shifters all the way into their neutral position (high gears for standard derailleurs, low for rapid rise) and then shift over into the neighbouring sprocket. If the chain doesn’t sit vertically under the sprocket or doesn’t shift crisply, you have an adjustment problem…

Front derailleur: clean and oil If your front derailleur is on strike, your first remedy is a good clean with a long soak in light oil (WD40, GT85, Superlube). Periodically work the derailleur back and forth as far as you can – gradually increasing until you work across the full range of movements. This is easiest with the chainset removed. Dirt will probably ooze from the pivot points as you go. Wipe it off. Oil all the pivot points carefully. Use the shifter to slacken off the cable; shift it into the smallest chainring position. Take hold of the derailleur cage, pull it out from the frame as far as it will go, and push it back. Repeat a couple of times to work the oil into the pivots. Once…

Inspect cable and casing before you start – if either are kinked, frayed or corroded, it’s time to replace them. For gear cables, lift your back wheel off the ground. Shift into the largest sprocket front and rear, then stop pedalling. Click your shifters as if changing into the smallest sprocket and smallest chainring For V-brake cables, squeeze the brake units together, slide back the rubber boot and release the noodle from its hanger. For mechanical disc brakes, push the actuation lever upwards, as if applying the brake. This creates slack in the cable. Follow the section of outer casing that emerges from the shifter or lever, to the cable stop on the frame. Pull the outer casing forwards and wiggle the cable out of the slot in the cable…

The procedure for changing cables is the same for front and rear shifters. Rear gear cables need changing more often because the section of cable near the back wheel gets filled with dust and mud easily, making your shifting sluggish. For either derailleur, cut off the cable end and undo the cable clamp bolt at the derailleur. Pull the cable gently out of each section of outer casing in turn. Work all the way to the shifter, so that you end up with bare cable hanging out of the end of the shifter. Follow the three steps below to fit the new gear cable to the shifter, then route the new cable back through the outer casing to each derailleur. It’s definitely worth changing the last section of outer casing…

Conventional / top- normal deraileurs (including Shadow) For the rear derailleur, push the cable through the barrel-adjuster on the back of the derailleur. Lift the back wheel off the ground and turn the pedals so that the chain returns to its neutral position – the smallest sprocket for most derailleurs, the largest for rapid-rise types. For rapid-rise, see below. Screw the barrel-adjuster all the way into the derailleur (turning it so the top of the barrel moves towards you), then back out a couple of complete turns. Look carefully at the cable-pinch bolt; there are often several possible ways to fit the cable under it, and only one of them makes your gears work properly. Look for a groove or a slot indicating the right place. The most common place…