Sometimes manufacturers uses the English-American standard and list the numbers in inches (for example, 26 x 1.9). In other cases, manufacturers write one number in inches and the other in millimeters (for example, 26 x 19).
Knowing the size of a wheel is important because not all wheels will fit a bike and not all tires will fit a wheel. The diameter determines what wheel will work with your bike. The forks on a bike are designed to use wheels of a certain size. If the diameter is too large, the wheel won’t fit on the bike. If the diameter is too small, the brakes won’t align properly with the rim.
The width impacts the tires you can use. Wider rims are usually found on mountain bikes, which use thick tires with heavier tread. Narrower rims are found on road bikes, which use thin tires.
Another consideration when buying wheels for your bike is the width of the hubs — the distance as measured between the two locknuts. It should match up with the distance between the dropouts in the forks and the rear frame dropouts.
Many quick-release hubs are thicker than their nutted, solid-axle counterparts. If your bike is designed with traditional hub nuts, be sure to test new wheels if they use a quick-release axle — otherwise, you may find that they don’t fit.
Other than size, another consideration when purchasing a wheel is whether it supports a clincher tire or tubular tire:
Clincher tires are what you find on most bikes today. A clincher combines a tire (which is secured on the rim by two beads, or outer edges, that tuck or clinch inside the rim) and an inner tube (which is enclosed by the tire). To protect the tube from the spoke holes, rim tape or some sort of material is used to line the inside of the rim next to the tube.
Tubular tires are found mostly on racing bikes. They consist of a tire material that is sewn together and then attached to the rim with adhesive. If you have a flat, changing a tubular tire is more work, but tubular tires are safer than clinchers if your flat occurs when you’re riding at a high speed, because they’re less likely to come off the rim while you’re riding.
Some downhill mountain bikes are starting to use a new style of rim and tire combination that doesn’t use tubes. These are more durable and hold up better to the extreme conditions of mountain biking, but they aren’t ideal for every rider because they’re very expensive and hard to work with.
Caring for your wheels
In order to maintain proper braking, you should keep your wheels clean and grease-free. Regular washings with soap and water will keep grime from building up. If you have trouble removing residue, try using a solvent and a Brillo pad to clean the rims. Use rubbing alcohol to finish the cleaning and remove all solvents and residue off the sides of the rims.
Make sure you keep the solvent away from the tire — solvent will cause the tire to deteriorate.
Another aspect of care for your wheels is keeping the hubs properly lubricated. At least once a year, overhaul the hubs. Most hubs today have rubber seals that keep a lot of contaminants out of the bearings. If your hubs don’t have rubber seals or you’re riding in dusty, rainy, or muddy conditions, you’ll need to overhaul your hubs and replace the grease more often.
You can do a number of things to extend the life of your wheels and keep them in good working order:
Properly inflate your tires. Tires act as the primary suspension for a bike. They cushion the wheel from blows and grip the road as you ride. The most important thing you can do to protect your rims is to keep your tires inflated to the psi indicated on the side of the tires. The number-one cause of damaged rims is under-inflated tires. Keep your tires at the right pressure and, when you hit the next pothole or rock in the road, you’ll have a good chance of your wheel surviving it intact. Plus, you’ll have the added benefit of not having to expend as much energy to pedal when your bicycle has properly inflated tires.
Make sure your spokes are properly tensioned. Wheels with spokes that are tensioned too loosely will have a shorter lifespan and could be dangerous. Loose spokes flex more than tense spokes do, so they fatigue more and are more likely to break. If several spokes give out, the wheel could collapse while you’re riding. A wheel with loose spokes will also flex and wobble, causing reduced steering control. At the same time, the answer to loose spokes is not to randomly or overtighten them. A wheel with spokes that over-tensioned can be dangerous as well. A wheel has a high risk of bending like a pretzel with under- or over-tensioned spokes.
You want a wheel with spokes that are tight enough that they don’t work their way loose while you ride. Frequently pluck the spokes of your wheel. Spokes of the same tension will make a similar sound, allowing you to quickly identify which ones are loose.
Make sure you have the right wheels. Just as important as inflating your tires and properly tensioning your spokes is to pair the right wheels and tires with the type of bike and style of riding you engage in. For example, if you’re going off-road, you should have mountain-bike wheels and tires, which are designed to absorb the impact of riding on a trail and other rough surfaces. For touring, you’ll want wheels with a greater number of spokes in order to support the weight of loaded pannier bags.
Talk to the staff at your local bike shop and let them know what kind of riding you’re planning on doing. They can match you up with the right wheels.
Many riders keep an extra pair of wheels in their garage for specific purposes. If they’re hitting the trail, they can take off and exchange their road wheels for a mountain-bike pair.
Wheel sets are one of the best ways to upgrade your bike. If you have a racing bike, new lightweight wheels with fewer spokes can greatly improve performance. If you’re starting to tour, some road riders convert to 650B wheels in order to use wider, touring-type tires.
Take care when you ride. The way you ride can have a significant impact on the life of your tires. Avoid making contact with objects in the road as much as possible. If you need to cross a curb, think about getting off your bike and lifting it over the curb. If you do have to impact something with your tires, lift yourself off the seat, bend your knees and elbows, and, using your legs and arms as shock absorbers, let your bike rise up over the object.
Inspecting the wheels for problems
Wheels are an amazing work of design. They require spokes that are properly calibrated in order to spin straight and smoothly. If any of the spokes are improperly tensioned, your wheel could come out of alignment or become unstable. Before you ride, take a moment to do a few checks to inspect your wheels:
Give the wheel a spin — it should continue to rotate smoothly for a period of time. It’s normal for the rear wheel to not spin as long as the front because of the drag of the cassette/freewheel. You shouldn’t hear any noises other than the rear cassette/freewheel.
Grab the wheel with one hand and the frame with the other, and try moving the wheel from side to side. If it moves side to side, the hubs may be loose and in need of adjustment or overhaul. (See the “Overhauling the hubs” and “Adjusting a hub” sections, later in this chapter.)
Spin the wheel and keep your eye fixated on the brake; watch the rim as it passes by. If it is not perfectly centered, it may need to be trued. (See the “Truing a wheel” section, later in this chapter.)
Pluck the spokes of the wheel and listen to the sounds they make. They should make a similar sound if they have the same tension. If one feels loose or makes a unique sound, it may need to be tightened.
Check the PSI in both tires with an air pressure gauge. Don’t go by the feel of your tires — take the time to test them with a pressure gauge.
Inspect the tread depth and condition of the tires sidewalls, looking for dry rot, deformities, or slices from road debris.
Often, tire sidewalls start to corrode or oxidize, vastly reducing their integrity and lifespan. Consider occasionally applying Armor All or similar vinyl/rubber protection to the sidewalls using
a clean rag.
Taking off a wheel
Before you can remove a wheel, you need to loosen the brakes. Brakes are designed to grip the rims, which are narrower than the tires, so their position prevents the wheel from being removed.
Most brakes are designed with a mechanism to allow for a quick release of the cable that holds the brake adjustment in place. The way in which you’ll detach the cable may vary depending on what type of brakes your bike has. On some brakes, such as cantilevers, you pull the end of the cable out of the brake arm.
In most cases, you need to pinch the brakes together to create slack in the cable, enabling you to lift the end of the cable out of the brake arm. After you remove the cable and release the brakes, the brakes will spring open. Here’s how to do this for the two main types of brakes:
If you have V brakes, you’ll need to pull back on the rubber boot of an L-shaped piece to expose the cable. Pull the cable out of the narrow slot in the cable holder and release it to open the brakes.
If you have side-pull brakes, there will be a small lever on the brake where the cable is attached. Move the lever to the open position and the brakes will spread apart. In some cases, there may be a button instead of a lever; if you have a button, push it to release the tension on the brakes.
Some bikes have the quick-release mechanism built into the brake lever. If you can’t find it on the brakes, look here.
If you can’t figure out how to release the brakes, you can always let the air out of the tires. Sometimes this will provide enough clearance between the brakes to remove the tires.
After you’ve released the brakes, follow these steps to remove the front wheel (start with the front wheel — it’s the easier of the two):
If your wheel uses hub nuts or bolts, use a wrench to loosen the axle (as shown in Figure 7-1). Start with one nut, loosen it slightly, and move to the other nut, switching back and forth until you can free the wheel.
Figure 7-1: Removing a wheel with bolts.
Avoid loosening one side all at once because this could lead to problems with the bike’s hub bearings. Alternatively, if you have two wrenches, you can undo both nuts at the same time.
In place of bolts, many bikes these days are manufactured with a quick release which are loosened by opening the lever on the side of the wheel hub. If your wheel has a quick release, open the lever. When you release the lever the axle may loosen enough to remove the front wheel. If it doesn’t, hold the nut opposite the lever with one hand and rotate the lever a few times to loosen it (as shown in Figure 7-2). The quick-release skewer is shown in Figure 7-3.
Modern bikes are designed with a safety retention device built into the dropout which holds the wheel in place even when the quick-release lever is loosened. There are many different designs, so inspect yours and/or refer to your owner’s manual. In order to release the wheel, you have to lift and maneuver the wheel off the dropouts of the frame.
Figure 7-2: Removing a quick-release wheel.
Figure 7-3: The quick-release skewer.
Unlike the front wheel, which drops off as soon as the axle is loosened, the rear wheel requires another step or two to remove it because of the chain and derailleur being attached to it. Here’s how to remove the rear wheel:
1. Shift to the smallest cog on the rear, making the chain more slack.
2. Loosen the nuts or the quick release for the rear wheel in the same manner as you did for the front.
3. To remove the wheel, you may have to give it a slight blow to knock it loose from the frame.
4. When it comes loose, move the wheel away from the derailleur (forward and down) to let the chain fall off.
Don’t be afraid of the rear wheel. The chain and rear derailleur stay on the bicycle and, by removing the rear wheel, you won’t effect any of the gear adjustments. In some cases, you may have to use your hand to lift the chain off the cogs or pull back the derailleur from the wheel in order to slack the chain from the cogs.
Repairing dents in the rim
Even if you keep your tires properly inflated and try to avoid obstacles in the road, at some point, if you ride enough miles, you’re bound to hit something that will cause a dent in the rim. If this happens to you, don’t despair. You don’t necessarily have to replace the wheel. Try these steps:
Use an adjustable wrench on the lip of the rim as a lever. Work little by little on the dent, being careful not to bend the rim too much in the other direction.
Put the rim into a vise. Tightening the vise sometimes will squeeze the dent out of the rim.
In the case of a dent on both sides of the rim, try laying the rim on a flat surface like a block of wood. Using a mallet, try flattening out one dent with a sharp blow. Turn the rim over and do the same to the other side.
Installing the front and rear wheels
Installing the front and rear wheels is a fairly simple process but one that should not be taken lightly. The wheels must sit firmly in the frame’s front and rear dropouts. If you have anything less than a tight fit, you could be risking the chance of a wheel coming loose, something that would be potentially disastrous if you were biking. Follow these steps and you’ll be in good shape:
1. Make sure that the brakes are open and there is room for the wheel to pass.
2. For the front wheel, align the hub with the dropouts in the fork and slide the wheel into place.
• If you have a quick-release hub, you may need to adjust the nut on the opposite side of the wheel before the quick-release lever can be closed. Be sure not to use the lever to crank the quick release to a tight position. Instead, turn the nut opposite the lever until it’s almost tight and then close the quick-release lever.
When you close the quick-release lever, the lever part should be loose in the open position, start to snug when sticking straight out away from the frame, and tighten fully when closed. It should require enough force that it leaves an indentation on your hand. Any looser and it may not be secure.
• For traditional hubs with nuts, begin by tightening the axle nuts, alternating side to side a little at a time until both are securely in place.
3. For the rear wheel, start by making sure the right hand shifter is placed into the highest gear.
Hold the rear derailleur from the metal tab at the bottom pulley in order to open up the chain into a large loop. Make sure the rear cassette goes into the middle of this loop as you install it.
4. Maneuver the wheel into place so that the top part of the chain just above the derailleur falls onto the smallest sprocket.
5. With the chain sitting on the smallest cog, which is the cog it was on when you removed the wheel sprocket, slide the wheel into place into the rear dropout part of the frame.
6. Use the same procedures as you did for the front wheel to fasten the quick release or the axle nuts.
Hubba-Hubba: Working on the Hubs
Hubs have to hold up under significant pressure and, over time, water, dirt, and grime work their way into the bearings and can cause this pressure to wear them out. The best solution for keeping them in good working order is to perform an overhaul of the hubs at least once a year as part of your annual service — more often if you ride a lot or in wet or muddy conditions.
Hubs are designed to allow the wheel to effortlessly spin around an axle. Bearings inside the hub reduce friction as the axle rotates. If you hear a grinding sound or the wheel doesn’t rotate smoothly, it may mean that the hub is too tight and should be adjusted or that an overhaul is in order. If you can wiggle the axle back and forth, this may mean that the hub is too loose.
There are two main styles of hubs:
Cup-and-cone (see Figure 7-4): In the cup-and-cone style, loose ball bearings sit in smooth cup and are held in place by a cone. The cone and cup together create a race, in w
hich the bearings can move around the axle in a circle with minimal friction. Washers are used to properly space the cone and cup and a locknut holds everything in place on the axle.
Sealed bearing: The sealed-bearing hub is popular on many midrange to high-end bikes. This style of hub also has a an axle, bearings, race, and cone, but they’re assembled as a unit and sealed when they’re manufactured to improve their ability to keep water and dirt away from the bearings. Some sealed-bearing hubs can be serviced; others need to be replaced when they give out. The good thing is that they last much longer than cup-and-cone hubs.
Figure 7-4: A cup-and-cone hub.
Don’t be fooled by the label sealed mechanism. These are standard cup-and-cone-style bearings, except they have a rubber seal to help keep contaminates out. They aren’t true sealed bearings.
Overhauling the hubs
Well-functioning hubs are critical for smooth spinning wheels and a comfortable ride. To keep your hubs in the best possible shape, plan on overhauling the hubs at least once a year. If you’re lucky enough to have sealed-bearing hubs you’re off the hook; most of these will last many years without any service. If you have cup and cone hubs, follow these steps:
1. If you have a quick-release skewer, remove it from the wheel. If there are nuts on the hub remove them with a wrench, alternating side to side as you loosen.
2. Using a cone wrench and a second standard wrench, make sure the cone and locknut are tight against each other on one side of the hub.
3. On the other side of the hub, using a cone wrench, secure the cone in place while you loosen the locknut in a counterclockwise direction on the same side of the hub (see Figure 7-5).
It will usually require some force to initiate movement in the locknut. If you’re working on a hub with a freewheel, remove the freewheel (see Chapter 11 for instructions). If you have a cassette hub, work on the side opposite the cassette.
Bike Repair & Maintenance For Dummies® Page 11
