Bike Repair & Maintenance For Dummies®

by Dennis Bailey

  Figure 13-1: Using a pedal wrench to remove a pedal.

  Figure 13-2: Using a pipe for leverage.

  Remove the crank arm and then secure it with a vise. In this manner, you won’t have to worry about the crank arms moving while you try to loosen the pedal. Place a soft cloth around the crank arm so you don’t damage or scratch it.

  Be careful when trying to free a tight pedal. It’s very easy for the wrench, the crankarm, or your hand to slip while you’re applying force, which could cause you to smack your hand or arm against your bike. Wear a pair of work gloves to save your knuckles from being scuffed up on the chainrings.

  Overhauling the pedals

  Pedals depend on internal bearings to spin smoothly. Over time, the bearings wear out causing the pedals to spin less smoothly, which reduces performance. This section describes some steps you can take to overhaul the pedals. For cheaper pedals, overhauling isn’t an option, because they’re made too cheaply to be serviceable. For higher-quality pedals, an overhaul is a good way to extend their life.

  As you take apart the pedal, place each component on a clean flat surface in the order it was removed. This will help you reinstall the components in the correct order.

  Here’s how to overhaul your pedals:

  1. If the pedal has a flat medal cage, remove it before beginning to overhaul the pedals.

  This will make working with the pedal easier. There should be several screws holding it in place, which can be removed with a screwdriver or Allen wrench.

  2. Remove the dust cap with a small flathead screwdriver.

  Be careful not to damage the dust cap.

  3. Loosen the locknut under the dust cap, holding everything in place.

  To reach the locknut, you may be need to use a socket wrench.

  4. If there is a washer in place, remove it.

  If the washer is difficult to lift out, use a flathead screwdriver or needle-nose pliers.

  5. Remove the cone that is holding the bearings in place.

  The cone may lift out or need to be unthreaded with a screwdriver or needle-nose pliers.

  Make sure you’re supporting the axle. If the axle drops out, the bearings will fall out and you’ll be searching for them on the floor for hours.

  6. Scoop out all the bearings and inspect their surfaces.

  If they’re dull and have dents, they need to be replaced.

  7. Clean all the parts, and then install them in reverse order from how you disassembled them.

  Be sure to apply a liberal coat of grease inside each side of the pedal. This will help hold the bearings in place until you thread the cone, washer, and locknut back on.

  8. Finish the reassembly by refitting the dust cap.

  This is important to keep dirt and water out of bearings and ensure that your overhaul lasts.

  Installing new pedals

  Many pedals are marked with an L or an R to help you figure out which pedal should go on which side. You want to make sure you have the correct pedal, because the left pedal unscrews in a clockwise direction and the right pedal unscrews counterclockwise. If you try to screw in the wrong pedal, you’ll damage the threads.

  To install new pedals, follow these steps:

  1. Apply grease to the threads of each pedal (as shown in Figure 13-3).

  2. Start with the right pedal, and remember that you’ll be turning the pedal in a clockwise direction.

  3. To ensure that you don’t damage any threads, screw the pedal in by hand using care (as is shown in Figure 13-4).

  Figure 13-3: Lubricating the pedal.

  Figure 13-4: Reattaching the pedal.

  4. When the threads engage, use the wrench to tighten the pedal.

  One way to tighten the pedal is to use one hand to keep the wrench on the pedal’s wrench flats and then, with the other hand, rotate the opposite crank arm to tighten.

  Tighten until the pedals are secure, but don’t overtighten. Carefully check the crank arm for any metal shavings at the base of the pedal and, if necessary, remove them with a file.

  5. Repeat steps 1 through 4 for the left pedal, except screwing it in a counterclockwise direction to tighten.

  Crank It Up! Working on the Crankset and Bottom Bracket

  The two major components of the drivetrain are the crankset and the bottom bracket (see Figure 13-5). In this section, we explain how to service different types of crank arms and the two major types of bottom brackets — cartridges and adjustable bottom brackets.

  Figure 13-5: The crankset and bottom bracket.

  The crankset

  The crankset plays the leading role in moving you forward when you bike. Consisting of the cranks, the chainrings, and the bottom bracket assembly, the crankset’s job is to transfer power with the chain from your legs and the pedals to the chain and back to the rear wheel.

  On the crankset, the crank and chainrings play important roles. The cranks are what connect the pedals to the bike, and the chainrings guide the chain as it receives the force from the turning cranks.

  Of the different cranksets on the market, there are three main categories:

  One-piece: Children’s bikes and some low-end adult bikes have one-piece cranksets, where the crank arms are one, long, S-shaped piece and the bottom bracket has two large bearing retainers that are serviceable and adjustable. One-piece crankset are made to be fairly durable to hold up to the kind of abuse a kid can dish out on bike, but as you might expect for a low-end product, they’re heavy and not designed for performance.

  Cottered: Older bikes tend to have cottered cranksets. These consist of separate crank arms that are attached to the bottom bracket axle using a tapered metal pin. A hammer or a special tool is used to put these pins in place, after which nuts are attached to keep them secure.

  Cotterless: Newer bikes are built with cotterless cranksets. These are higher-performance parts with crank arms that come in a variety of sizes and styles and are built from more expensive materials that are lighter and stronger. Cotterless cranks are held in place by a nut or a bolt or in some cases by pinch bolts on the left-side crank.

  In the following sections, we tell you how to remove and install all three types so you can work on them.

  Removing and installing a one-piece crankset

  To remove a one-piece crankset, follow these steps:

  1. Use a wrench to unscrew the lockring in a clockwise direction.

  2. When it’s loose, remove it by lifting it over the crank arm.

  3. Place a chisel in the slot of the slotted retainer, which sits under the lockring.

  4. Tap the chisel lightly with a hammer in a clockwise direction.

  5. When it’s loose, remove it by lifting it over the crank arm.

  6. Pull the entire crank assembly out of the bottom bracket shell.

  7. Use the chisel and hammer to lightly knock out the bearing cups that sit within the bottom-bracket shell.

  To install the one piece crankset, follow these procedures in reverse.

  Removing and installing a cottered crankset

  On some older bikes, cranksets are attached using a cotter pin, which has to be removed and installed with a blow of a hammer (as shown in Figure 13-6). Remove the nut and washer from the pin using a wrench. Drive the pin out by hitting it with a standard (not rubber) hammer.

  If you have trouble moving the pin, use some penetrating oil and then try using a punch (a chisel-like tool with a pointed end). Many times, whether you’re using a hammer or another tool like a punch, the pin will have to be replaced because the removal process will likely damage it.

  To install a cotterless crankset with a socket bolt, follow these steps:

  1. If the pin was not damaged during removal you can reuse it. Otherwise, take the old one to your local bike shop to buy a replacement.

  Figure 13-6: Removing the cotter pin.

  2. Slide the crank arm onto the crankset and insert the pin.

  3. Hammer the pin until it is firmly set in the crank a
nd exposed on the other side.

  4. Put the washer and bolt on the end of the pin and tighten with a wrench.

  Removing and installing a cotterless crankset

  Cotterless cranksets are held in place in one of three ways: with a socket bolt, by a nut and bolt, or by pinch bolts. The method for removing the crankset varies depending on how the crankset is held in place. We cover all three in the following sections.

  With a socket bolt

  Most bikes these days have cotterless cranksets that are attached with socket bolts. (These cranksets are sometimes called one-key release.) This type of crankset is easy to remove because it has a crank extractor built in (see the next section for more on extractors). There is usually not a dust cap, but if there is one, you can use a screwdriver to remove it.

  Using an extra-long 7mm or 8mm Allen wrench, turn the bolts in a counterclockwise direction, holding the cranks from moving with your free hand (as shown in Figure 13-7).

  Figure 13-7: Loosening a cotterless crank with a Allen wrench.

  To install a cotterless crankset with a socket bolt, follow these steps:

  1. Apply grease to the threads of the nut or bolt.

  2. Insert the right crankarm into the right bottom bracket.

  3. Insert the left crankarm onto the end of the axle of the right crankarm, and screw in the bolt, being careful to align the threads.

  4. Tighten the bolt to secure the crankarm.

  This type of crankset usually doesn’t have a dust cap, but if there is a dust cap, grease the threads and install it.

  With nuts and bolts

  To remove a cotterless crankset that’s held in place with nuts and bolts, you need a crank-arm extractor (see Figure 13-8) that fits your bike. One side of the crank extractor is used to remove the bolt holding the crankarm on the axle. The other side of the extractor allows you to remove the crankarm.

  Here are the steps to take:

  1. Use a screwdriver and remove the dust cap that covers the threads inside the crank arm.

  Be careful not to damage the dust cap.

  2. Fit the extractor onto the nut or bolt inside the crank arm.

  3. Using a wrench, turn the extractor in a counterclockwise direction.

  4. When the nut or bolt is loose, use your fingers to remove the nut or bolt.

  If there is a washer with the nut or bolt, make sure to remove that as well.

  5. Thread the other side of the extractor into the threads of the crank arm.

  Be careful to make sure that the threads are aligned and that the extractor is not being screwed in at an angle.

  6. When it becomes too difficult to turn the extractor, use a wrench and continue to snugly screw the extractor into the crankarm until it gently pushes against the axle.

  7. Turn the handle of the extractor to push the center core of the extractor against the axle.

  It will eventually push the crank off the axle.

  The extractor is actually two tools: a 14mm or 15mm socket wrench and, separately, a threaded center pushing extractor tool. Sometimes these tools are integrated as one tool with two sides.

  Figure 13-8: Using the crank-arm extractor.

  To install a cotterless crankset with nuts and bolts, follow these steps:

  1. Apply grease to the threads of the nut or bolt.

  2. Insert the right crankarm into the right bottom bracket.

  3. Insert the left crankarm onto the end of the axle of the right crankarm and screw in the nut or bolt, being careful to align the threads.

  4. Tighten the nut or bolt to secure the crank arm.

  5. If there is a dust cap, grease the threads and install.

  With pinch bolts

  Some manufacturers including Shimano make cranks that are held in place by pinch bolts on the left crank arm. These types of cranks do not require a crank arm extractor for removal.

  Here are the steps for removing a cotterless crank held in place with pinch bolts:

  1. Loosen the pinch bolts on the left crank arm.

  2. Remove the cap on the left crank arm.

  To remove the cap, you may need a special tool. In some cases, caps are designed to be removed with an Allen wrench.

  3. Pull off the left crank arm.

  4. Pull off the right crank arm.

  If it’s tight, give the end of its axle a light tap with a rubber hammer or mallet. Be careful not to mar your crank arm during this procedure.

  To reinstall cotterless crankarms with pinch bolts, follow these steps:

  1. Insert the right-side crankarm with the chainrings into the bottom bracket, with the crank arm pointing downward at the six o’clock position.

  2. Insert the left crankarm into the bottom bracket, with the crankarm pointing upward to the 12 o’clock position.

  3. On the end of the axle of the right crank unit, there will be threads with one groove larger than the other. Align this larger groove with the groove on the inside of the left crank arm.

  This assures that both arms are exactly 180 degrees apart.

  4. Apply grease to the ends of the cap and insert it into the center of the left crankarm.

  5. Apply grease to the threads of the two pinch bolts and insert them into the left crank arm.

  As you tighten, switch between the bolts every few turns to make sure they tighten evenly.

  For Shimano cranks of this type, make sure to tighten the threaded dust cap that actually helps bind the crank. Provided with your cranks is a small tool used to hand-tighten this piece before you tighten the pinch bolts.

  Working on chainrings

  Over time, the chainrings will wear down, making shifting more difficult. If you have an old, stretched chain on your bike that you haven’t replaced in a while, this will cause the teeth on your chainrings to wear out. Likewise, worn teeth on chainrings will cause accelerated wear and stretching of the chain. Normally a chain will wear out faster than the chainrings. If you regularly check your chain for wear and replace it at the first signs of wear, you’ll be able to get two to three chain lives before you need to replace your chainrings.

  Chainrings that need to be replaced have teeth that are thinner and look like waves from the ocean as opposed to cleanly cut teeth (the way they look when they’re first manufactured). To remove chainrings, find a clean, flat surface, and follow these steps:

  1. Use an Allen wrench to remove the bolts holding the chainrings in place (as shown in Figure 13-9).

  Figure 13-9: Removing chainrings.

  2. Use a flathead screwdriver or a special slotted wrench (as shown in Figure 13-10) to hold the nuts in place while you use the Allen wrench.

  3. After you remove one chainring, there may be another set of bolts holding the other chainring(s) in place. If so, remove these as well.

  Be careful to hold onto any spacers when you remove the chainrings. You’ll need to put these back in place if you’re replacing or remounting any of the chainrings.

  If you end up in an accident or run the side of your bike into something, you could bend the teeth on a chainring. If this causes a tooth to break or leads to serious damage to the overall chainring, you’ll probably want to replace it. However, if just one tooth or a few teeth are slightly bent, causing shifting and chain problems, you may be able to bend them back in place. Bike shops have a special chainring tooth alignment tool that is designed for this procedure. In some cases, you may be able to do the job with an adjustable wrench, although this is a little riskier.

  Figure 13-10: Undoing chainring bolts.

  To straighten chainring teeth, follow these steps:

  1. Spin the chainring without the chain to identify which tooth or teeth are bent.

  If the bent tooth or teeth are on the large chainring, sometimes you can straighten it or them without removing the chainring from the bicycle. If not, you’ll need to remove the chainring.

  2. If you removed the chainring, secure it in a vise as close to the bend and with as much of the chainring being support
ed or clamped in the vise as possible.

  Cover the chainring with a soft cloth so you don’t scratch or damage it with the vise.

  3. Using the chainring tooth tool or an adjustable wrench, grab the tooth, being sure not to grab the chainring itself.

  If you use an adjustable wrench, tighten it onto the tooth as snugly as possible.

  5. Bend the tooth slightly in the other direction to straighten it.

  Only try to bend or straighten one tooth at a time.

  6. Place the chainring on a flat hard surface and examine your efforts.

  Reinstall the chainring by inserting the bolts that hold it in place and reversing the steps you used to remove it. If nuts are used to hold the bolts in place, insert these and tighten. Once you’re finished, test the chainring to make sure the chain shifts and runs smoothly around the chainring.

  The bottom bracket

  Crucial to the crankset is the bottom bracket. Of all the bearings on a bike, the bottom bracket is the one that has to bear the heaviest load. Not only does the bottom bracket have to spin while you pedal, but it takes the force of all the twisting and turning that occurs during pedaling.

  There are two main types of bottom brackets:

  Adjustable: If you have an older or lower-end bike, you may have an adjustable bottom bracket. This type of bottom bracket has a cup that holds bearings and an axle that spins within the bottom bracket. An adjustable bottom bracket is much more susceptible to wear and tear than a cartridge-type (see the next bullet), because water and dirt can enter the cup where the bearings are held. Plus, an adjustable bottom bracket needs to be adjusted perfectly, or the bearings will prematurely wear out.

  If you have this style of bottom bracket you may want to think of upgrading to a cartridge bottom bracket. At the very least, you’ll want to overhaul the bottom bracket at least once a year — more often if you do a lot of biking in wet or muddy conditions.

  Cartridge: Most newer bikes have a sealed-cartridge style of bottom bracket. A cartridge has a longer life than an ordinary bottom bracket — because they’re sealed, water and dirt are kept away from the bearings. They’re also easier to install and maintain because they don’t need to be adjusted the way standard bottom brackets with cups and cones do.