A balanced wheel is one whose rim is centered directly over its axle. A balanced wheel is achieved when the spokes connecting the rim to the axle are properly tensioned, keeping the rim even and strong. A lack of proper tension in the spokes will cause the rim to pull to one side, or bulge, at the very least leading to ineffective braking. Keeping your wheel balanced is integral to the performance of your bicycle and potentially your safety. To balance your wheel, follow these simple steps.
Remove your wheel from the bike and place the axle in the truing stand arms. If you do not have a truing stand, leave the wheel on the bicycle and use the brake pads as a reference marker.
Turn the wheel. Take notice of any bulge in the wheel. A wheel that has a bulge will not run evenly past the brake pads, or in the case of a truing stand, the truing stand jaw tips.
Pluck the spokes near the bulge in the wheel. A loose spoke will sound a dull "thud". Spokes that may be too tight will give off a high "ping."
Apply a small amount of oil to the nipples of these spokes. The "nipple" is where the spoke threads into the rim of the wheel and is the part of the spoke that will be adjusted with your wrench.
Use your spoke wrench to tighten, or loosen, the nipples of these spokes. A spoke that is loose will cause the wheel to bulge opposite the spoke. A spoke that is too tight will cause the wheel to bulge in the same direction as the spoke. By making the proper adjustment with your spoke wrench, you will eliminate the bulge, bringing it back in line with the remainder of the wheel.