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This fourth and final part of the wheel-building series is your insurance. It will help you protect the time and money you've invested in creating a fine set of wheels (or just the money if you opted to buy instead of build). We'll see how to keep new wheels rolling smoothly, and how to fix some problems you might run into. A well-maintained wheel saves money because it should last longer than one that's regularly allowed to deteriorate until it must be repaired. When a problem is caught and fixed early, the risk of permanent damage is lessened. A wheel that's round and true rides smoothly and brakes safely. Dented or bent rims can cause brakes to grab, which impairs stopping efficiency and can cause skids that damage tires. Finally, nobody likes to have a mechanical problem interrupt a ride. A wheel inspection takes little time, and minor repairs can be made within minutes right in the garage. Once a month, take the time to evaluate your wheels' condition. Remove them from the bike, then use a soft brush and soapy water to scrub the tires and rims. Rinse well and wipe dry with an old towel. Under a strong light, inspect the tread for pieces of glass, gravel, a thorn, etc., which could work through and cause a puncture. Then check the sidewalls for casing bruises or small cuts. Wipe off the spokes and hub. Use solvent on the corner of a rag to loosen any foreign material. Some people choose kerosene, which leaves a very light residue, while others prefer a product that evaporates completely, such as the nonflammable paint preparation solvent available at automotive stores. Whatever your choice, do not allow the solvent (or the soapy water) to get into the hub bearings. And always keep solvent away from tires. If any brake pad residue has built up on the rim, remove it with steel wool and wipe the surface clean. After everything is clean and dry, inspect the following: Hub - A loose or bent axle can make the rim seem out of true. Look directly into the end of the axle and rotate it from the other side (and then reverse sides). If it oscillates, it's bent and should be replaced. Turn the axle and wiggle it back and forth to check for excessive play or tightness; adjust the cones if necessary.* If the axle seems properly adjusted but feels rough when you turn it, open the hub for an inspection. There may be internal damage, or it might just need cleaning and lubrication. Rim - Look carefully around the spoke holes for signs of cracks or bulging. If an area looks suspicious, tag the spoke(s) with a piece of tape for the next step. Watch for dents, which spread the rim's sidewalls and usually create a flat spot on its circumference, and bends, which make the rim out of true. Both conditions diminish riding comfort and stopping ability. Spokes - Check for spokes that are broken or have vibrated loose by squeezing pairs together. Never leave a broken spoke free to snag something and cause more damage or an accident. If you can't replace it right away, unscrew it from the nipple and remove it from the wheel, or weave it securely through other spokes so the end is inside the wheel. Check trueness by spinning the wheel in the frame or truing stand. This visual inspection will tell you a lot; so will spoke tension. *Quick-release hubs should have some play in the axle bearings when the quick-release isn't tightened. How much? Experiment by placing a wheel in the frame and lightly tightening the quick-release. You should be able to feel some side-to-side play at the rim, but this should disappear when the quick-release is fully tightened. During wheel truing however, adjust out all play until you're done, then put it back in.
The March article discussed the importance of equalizing spoke tension during construction. This is crucial to the life of a wheel, and equal tension is just as important during wheel maintenance. As we say at Wheelsmith, don't just be a wheel truer, be a tension detective. If the wheel is trued without regard to maintaining equal spoke tension, there will be problems down the road. Start at the valve hole and work around the wheel, squeezing pairs of spokes to check relative tightness. (See photo 1.) You can audibly confirm your findings by tapping each spoke lightly with a screwdriver shaft and listening for odd notes. Tag the spokes that feel different or ring noticeably higher or lower. I know a builder who keeps color-coded alligator clips for this purpose -- red for tight spokes, blue for loose ones. This check of spoke tension should be performed twice a month, or about twice as often as your wheel cleaning and inspection. If there is no wheel damage but the rim is wobbling, the repair is simple. Before you begin truing, put a small drop of penetrating oil into each nipple where the spoke enters (unless a thread preparation compound was used during wheel construction). Also put a drop where each nipple comes through the rim. This lubrication reduces friction that can bind nipples and produce false tension. A wobble that develops in a new wheel is often caused by just one or 2 spokes that were wound up or not quite seated in the hub. Feel for spokes that are looser than their neighbors. The fewer spokes you involve in retruing, the faster and better your repair will be. Tag tight and loose spokes, and see if there's a way to true the wheel by equalizing their tension. When a spoke is damaged or broken, the rim will be out of true at that spot. Unless the wheel is brand new, remove the tire so you can replace the nipple as well as the spoke. An old nipple may bind on new threads, making you think the spoke is tighter than it is. Remember to weave the spoke's final cross. If this bends the spoke a bit, straighten it before threading it into the nipple. Next, tighten the spoke until its tension equals those surrounding it (front wheel) or those going to the same hub flange (rear wheel). This should result in almost perfect trueness if the wheel was properly built. Let's say, however, that the wheel remains out of true and/or round, or the wheel was almost true before you replaced the damaged spokes. This means the rim is bent. As mentioned in previous articles, a bent rim makes it difficult to achieve balanced spoke tension, which is the key to long-lasting trueness. If the wobble isn't too bad, try loosening all spokes 2 or 3 turns, 1/2 turn at a time, to return to a Ground Zero tension level. Then retighten to equalize spoke tension around the problem spoke(s). With experience you'll be able to tell whether the tension distribution is equal enough for the wheel to stay true. If it isn't, you have 2 choices: try to repair the rim, or replace it. Dents occur when tires are underinflated and you hit railroad tracks, curbs, potholes, etc. This widens the rim and causes the pads to grab during braking. Press the dented section in with a smooth-jawed vise, proceeding very carefully. You can also use pliers if they're large enough to hold 2 pieces of flat metal against the sides of the rim to protect it. Don't press too far. Although a section of rim that's too narrow is better than one that's too wide, it's still not good. Smooth over any nicks or deep scratches with medium sandpaper (120-180 grit).
If the flat spot that almost always accompanies a dent is apparent as you ride, you probably won't be able to remove it by adjusting spoke tension. You'll have to unbend the rim. Start by unscrewing nipples several turns in about an 8-spoke region of the flat spot, then fully loosen the 2 spokes at the center. Suspend the rim with the flat spot centered on a round, secure object such as the anvil of a vise, and pull down. (See photo 2.) If you need more room, unscrew and push aside the 2 center spokes. Slowly increase force until you feel the rim give, then retighten the spokes and true the flat section.
An alternative method requires a helper to hold the wheel (prepared the same way) with the flat section down. Place a piece of 2x4, preferably rounded to fit the rim, on top of the flat section. Strike the wood with a hammer, progressing from light strokes to heavier ones until the rim is once again curved. (See photo 3.) Inspect the metal for cracks or wrinkles; their presence means it's time for a new rim. Rebuild, tension, and true the wheel. If spoke tension in the repaired section is about equal to that of the rest of the wheel, you'll probably get a fair amount of additional service from the rim.
A bent rim looks like it's out of true, but truing it makes some spokes very tight, others very loose. Even if the rim becomes straight enough to ride, it won't stay that way very long. To straighten a bend, reduce the spoke tension of however many pairs of spokes are necessary to span the bad area. Then place the wheel flat on a hard floor with the bent section closest to you and the bowed side down. (See photo 4.) With your hands about 10 inches to either side of the bend, press down on the rim until you feel it give. Check to make sure you haven't pushed in the lip of a clincher rim (you may be able to bend it back with pliers) and look for cracks or wrinkles. Then retension and true the wheel. One bend can be remedied this way if it isn't too large. On the other hand, if a crash leaves a wheel with the contour of a potato chip, the rim must be replaced. Remember, the goal in all these repairs is to recreate balanced spoke tension in the wheel, not just make it visually true again. That's the key to ensuring that well-built wheels will continue to provide safe and reliable performance.
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