Bike Repair & Maintenance For Dummies®

by Dennis Bailey

  4. Insert the nipple through the rim, and tighten it using a spoke wrench from your emergency tool kit.

  5. Tighten the spoke to a tension where it makes a similar sound when you pluck it like a harp as the sound made by plucking the rest of the spokes.

  6. Spin the wheel to see if it has a bend and adjust the spoke tension to straighten it if needed.

  Figure 4-2: A broken spoke wrapped around another spoke.

  Fixing flats and torn tires

  You should always have your patch kit available when you ride, because sooner or later a flat will sneak up on you. (For instructions on how to change a flat, see Chapter 6.) It’s also good to have a spare tube on hand in case a tube blows out and can’t be patched.

  Before you reassemble the wheel, don’t forget to inspect the tire and tube for the sharp object that caused the flat. Otherwise, you might be stuck on the side of the road repairing a flat in another five minutes.

  If you have a torn or ripped tire, you’ll want to fix it as soon as possible or risk blowing the tube — especially if the tube has started protruding out through the tear. Bike stores sell tire boots, which you can use to reinforce the inside of the tire where the cut is located. If you don’t have a tire boot, there are a number of alternatives that’ll do the job. Dollar bills, duct tape, food wrappers, plastic cut from a soda bottle — you’re only limited by your imagination. (To repair or boot a tire, see the steps in Chapter 6.)

  Repairing a broken chain

  A broken chain is a pretty infrequent event, though as newer chains are manufactured to be narrower this occurrence is becoming increasingly more common. When a chain breaks, the outer plates on one of the links are twisted and/or ripped off, causing damage to the link and possibly to your bike. You can repair the chain in an emergency, but as soon as you get home, you should replace it.

  To repair a broken chain:

  1. Remove the chain from the bike and, using a chain tool from your emergency tool kit, remove the affected link or links.

  Follow the instructions in Chapter 10 for using the chain tool.

  2. If you have extra links, use the chain tool to connect the extra links to the chain, replacing the damaged links.

  If you don’t have extra links, you can shorten the chain by removing the faulty links and reconnecting the chain. However, you most likely won’t be able to shift into the gears when the chain is in the larger cogs in the rear and the largest chainring in the front.

  3. Reconnect the chain using the chain tool and following the steps in Chapter 10.

  Examine all the rivets and links to be sure that there are no other weaknesses in the chain.

  Extracting a jammed chain

  A jammed chain (like the one shown in Figure 4-3) can be one of the most annoying malfunctions when you’re riding. A jammed chain often happens when the front derailleur shifts the chain too far inward and over the smallest chainring. It can also be caused by a worn chainring not grabbing the chain properly or mud clogging the chain and chainring.

  Figure 4-3: A jammed chain.

  Dennis has had this happen to him while shifting into his smallest or “granny” gear during a steep climb. Trying to stop pedaling when you’re on a sharp incline on a bike loaded down with pannier bags is awful — it takes all your energy not to fall over and become fresh roadkill.

  The best thing to do when you hear a loud, grinding sound when you shift is to stop pedaling immediately. If you continue to apply force to the pedals, you could further jam the chain and make it even more difficult to remove.

  To extract a jammed chain:

  1. Try pulling on the chain to separate it from the chainstay and chainring.

  Be careful not to twist it — you don’t want to damage the chain in any way.

  2. If pulling on the chain is not enough to free it, try rotating the cranks backward while you pull the chain.

  This is often enough to spring the chain loose. If not, move to Step 3.

  3. Insert a screwdriver between the chainring and chainstay and, using it as a lever, gently pry open the space.

  This should allow you to slide the chain out (if not, move on to Step 4). Check the chainrings for any damage caused using this method and straighten as necessary.

  4. Separate the chain with a chain tool.

  Note: This step should only be used as a last resort, when all the preceding steps fail.

  Dealing with the derailleur

  If the front derailleur gets hit or the chain gets stuck when you try to shift, the derailleur can become twisted or bent. If the derailleur moves out of place by twisting on the seat tube, you’ll want to move it back into place.

  Follow these steps to adjust the position of the front derailleur:

  1. Loosen the derailleur clamp bolt, which keeps it attached to the seat post.

  Usually a 5mm Allen wrench or 8mm box wrench will do the trick.

  2. Position the derailleur so that its cage is parallel with the chainrings and only 1mm above the top of the largest chainring.

  3. Retighten the clamp bolt.

  See Chapter 14 for more details on installing a front derailleur.

  If the derailleur is bent or damaged, you’ll need to remove it and continue your ride without it. Follow these steps to remove the front derailleur:

  1. Remove the screw at the back of the front derailleur cage.

  2. Separate the cage and remove the chain.

  3. Bypass the derailleur and place the chain on the chainring that will best serve you on your ride home.

  4. Remove the clamp bolt holding the derailleur to the seat tube, disconnect the shift wire, and detach the derailleur from the bike.

  You’ll need to move the shift wire into a position out of the way or completely remove it.

  Like the chain, the rear derailleur is a very exposed part of the bike. It sticks out and has very little protection. If you brush up against or hit something while you’re riding, you can easily bend or damage it. A bent rear derailleur frequently is the result of a bike that falls over on that side.

  Most mountain bikes use a replaceable derailleur hanger that is designed to fail before the expensive derailleur itself would. In this case, buy your bike’s replacement hanger, and keep it with you when you ride.

  Although modern rear derailleurs are precise instruments that are sensitive to the slightest adjustments, if you’re in a jam and a bent rear derailleur is causing your from finishing your trip, you can try manually bending it back into place. You can do this by inserting an Allen wrench into the mounting bolt and pulling upward while you pull the S-shaped cage away from the bike using your other hand, as shown in Figure 4-4.

  Figure 4-4: Unbending a bent rear derailleur.

  If you straightened out the rear derailleur enough to ride home, you may want to take it to your local bike shop to be properly tuned. Bike mechanics use a special rear derailleur hanger alignment tool to properly position the derailleur.

  If the rear derailleur is damaged beyond repair and won’t shift or allow you to continue biking, you’ll need to bypass the derailleur and turn your bike into a single speed. If this happens to you, follow these steps to get back on the road:

  1. Use a chain tool to separate the chain.

  See Chapter 10 for more information on separating and reconnecting a chain.

  2. Decide on a gear that is appropriate for your ride home.

  We recommend that you pick the middle chainring on triple-chainring bikes or the smallest chainring on two-chainring bikes and the middle cog in the cassette. Leave the rear derailleur on the bicycle.

  3. Hold the chain together to determine if there is any overlap in the two ends.

  If there is, you’ll need to remove some links in order to keep enough tension on the chain.

  4. After removing the additional links, reconnect the chain.

  Spin the cranks a few times to be sure that there is enough tension on the chain and that it won’t come off the chainring. If it doesn�
��t, you should be good enough to finish your journey.

  If a cable is old, worn, or frayed there is a chance one may break while you’re riding. If it’s a cable for the derailleurs, you’ll be limited in the number of gears you can use, but you’ll still be able to ride home.

  If the front derailleur cable breaks, the lack of tension will move the derailleur to the left and position the chain on the smallest chainring. If you have a triple chainring and want to use the middle chainring, pull the derailleur over the middle chainring and tighten the L-limit screw (shown in Figure 4-5) to keep it in place. For more details on adjusting the front derailleur, refer to Chapter 14.

  In the case of a rear derailleur cable break, the derailleur will move the chain to the smallest cog on the cassette. If you’re comfortable riding in this gear, you can finish your ride. However, if you need a more appropriate gear, you’ll need to adjust the rear derailleur. Keep in mind that there is only a limited amount of adjustments with this method and you might only be able to use one of the three smallest cogs. To make the adjustment, follow these three steps:

  1. Place the chain on one of the larger cogs.

  2. Use your hand to push in on the rear derailleur.

  3. Tighten the H-limit screw (shown in Figure 4-6) to keep the derailleur in place.

  Keep in mind that you may have to fine-tune the position of the derailleur so that the chain runs smoothly.

  Figure 4-5: The L-limit screw.

  Figure 4-6: The H-limit screw.

  Knowing When You Should Walk Home

  Certain repairs probably shouldn’t be attempted while you’re on the road. In some cases, you probably won’t have the tools with you. In other cases, the chance of a malfunction happening makes continued riding a dangerous proposition.

  Here are some situations when you should put away your emergency tool kit and start walking home:

  When your brake cables have broken: If you break a brake cable, you’ll be limited to half your brakes. Not only will you have reduced braking power, but applying only the front or rear brakes could cause you to have an accident. Squeeze too hard on only the front brakes and you wind up being thrown head forward over your handlebars. Do the same with the rear brakes, and you could skid out. When your front or rear brakes are out, your best bet is to walk your bike if possible or ride it home very slowly.

  When your crank is loose or has fallen off: If the crank has loosened or fallen off, it may be best to call it a day. The crank must be tightened with a significant amount of torque and this tightening is best done with the proper tools (including a torque wrench) and with the bike supported by a bike stand if possible.

  When your pedals are loose: Pedals can be secured with the proper wrench, but if you don’t have one available, you should walk your bike home. Riding with a loose pedal will damage the crank and could lead to an accident if the threads give out.

  When you have a problem with the bottom bracket: Working on the bottom bracket requires specialized tools that most riders wouldn’t consider taking along on a ride. If the bottom bracket comes loose or falls apart, don’t continue to ride.

  When your frame is damaged: A damaged frame is usually the result of an accident. If you’ve had an accident, you should immediately inspect the bike, paying particular attention to the frame. Besides looking at the frame from different directions to determine if it’s bent, you should inspect the frame close up, looking for cracks, especially in any welded sections, as well as cracks, bubbles, or ripples in the paint. (See the following section for more on what to do after an accident.). A damaged or bent frame undermines the integrity of the bike and increases the chance of an accident.

  Inspecting Your Bike after an Accident

  Even if you’re the world’s safest and most cautious biker, there’s always a chance you could end up in an accident. When you’re on a bike moving forward on two thin wheels, you’re completely exposed. Add in the fact that you’ll end up biking on busy roads, crowded bike paths, or the ever dangerous off-road trails, and you increase the odds that you’ll have a crash eventually.

  Always wear a helmet, wear biking gloves, and keep a cellphone and identification with you at all times.

  If you do end up in an accident, the first thing you should do is make sure you’re okay. The shock of being involved in a collision may keep you from realizing that you’re injured. If after checking yourself out, you’re lucky enough to have nothing more than a scratch or two, the next thing to consider is the state of your bike.

  Most modern bikes are designed with components and materials that can resist certain types of impact. However, in the case of an accident, you’ll want to thoroughly inspect your bike before getting back on it to ride. Something may have come loose or the collision may have caused a weakness in the frame or some other part of the bike that may become apparent later on down the road.

  Looking for looseness

  One of the simplest ways to identify if there is a problem with your bike after a crash is to check for looseness. Spend a few minutes to make sure that all the parts of your bike are still securely fastened and in place as they should be. You’re much better off finding a potential issue at this point rather than discovering it when the part falls off your bike.

  To check for looseness, perform the following steps:

  1. Straddle the front wheel pinching it between your thighs.

  2. Grip the handlebars and try to twist them side to side.

  3. Straddle the frame, squeeze the brakes, and try to rock the bicycle back and forth.

  If there is play in the handlebars or stem, it could mean either that the clamp bolts need to be tightened or you have a loose headset, something that could be dangerous at high speeds.

  4. While straddling the bike, use the handlebars to lift the front wheel off the ground.

  5. Drop the handlebars and let the bike hit the ground.

  If you hear any jingling or rattling, it could mean that something on the bike is loose. Repeat the procedure to isolate the location of the noise.

  Checking the alignment

  If your bike was involved in a collision, there’s a chance that something has been bent or broken and caused your bike to be out of alignment. Unless you visually inspect your bike, you may not notice that there is a concern. This is especially important with the frame, which helps keep you balanced, influences the bike’s handling, and provides stability. A crash can impact the integrity of the frame and make riding your bike a risky proposition.

  An important factor in how well a frame can hold up to a collision is the material it’s made of. Different frame materials offer varying levels of strength. Frames made of steel and steel alloys are amazingly strong, as are titanium frames. Aluminum frames, on the other hand, while having the benefit of being lighter than steel, are also weaker and fatigue over time. Carbon, which is a popular choice these days for frames, is made of up fibers that are arranged into a pattern, which gives significant strength to the material; however, carbon can be prone to breakage where the different tubes of the frame are connected.

  To perform an alignment check from the front of the bike, perform the following steps:

  1. Stand in front of your bike with the wheel between your legs and the handlebars in your hands, as shown in Figure 4-7.

  2. Eyeball the various angles of the frame.

  You should confirm that the head tube is parallel with the seat tube and that the top tube is in the same plane as the down tube.

  3. Look down at the forks to confirm that they’re evenly spaced around the wheel.

  To perform an alignment check from the back of the bike, follow these steps:

  1. Have someone support your bike while you stand behind it.

  2. Visually confirm that the seat tube and the head tube are in alignment.

  3. Check to see that the seat stays are straight.

  4. While you’re visually examining the frame, look at other parts of the bike, including the cranks and pe
dals and the front and rear derailleurs.

  The rear derailleur should be hanging straight down and be positioned under one of the cogs.

  Figure 4-7: Checking alignment.

  The All-Purpose Repair Tool: Duct Tape

  If you pack the emergency repair kit described in Chapter 16, you should be able to handle many of the basic emergencies that may strike when you ride. However, at some point, you may find yourself in a situation where a part of your bike needs repairing or replacing and you don’t have the tools to do the job, but you still need to keep riding. This is when you need to put on your MacGyver hat and get creative. A piece of wire on the side of the road may be good enough to secure a loose bottle cage. A PowerBar wrapper could be used to boot a tire. Really the only limit to bike repair and maintenance — at least as a temporary fix — is your imagination.

  Perhaps the most valuable of the multipurpose materials you can use to fix your bike is duct tape. Serious bikers always leave a roll in their bag for special emergencies. Duct tape is strong and secure, resists water, and can get you out of a number of jams. Here’s a list of some of the things you can do using duct tape and a little old-fashioned ingenuity:

  Hold a torn saddle together

  Keep a loose saddle post from coming off

  Secure a bike pump to your frame if the mounting bracket breaks

  Repair rips or tears in clothing, pouches, and pannier bags

  Attach a flashlight to your bike or helmet

  Hold together a cracked helmet at least until you can get home and replace it

  Hold together frayed cable ends

  Boot a torn tire

  Secure a broken buckle on a shoe

  Hold a bottle on a bike if the cage falls off

  Any and all repairs, patches, and fixes using duct tape are temporary and must be replaced at the earliest possible time.