Anyone who has witnessed a washing machine walking its way across the basement floor can understand how important balancing the load on rotating objects can be. Some people mistakenly think that, because modern wheels have gotten so much lighter and better balanced, they don’t need to balance wheels when fresh tires are installed. This is wrong. Even the smallest difference in weight is amplified many, many times as the wheel rotates. Also, your tires will wear more evenly and your bike will be more stable with balanced tires.
Balancing a wheel starts with a basic assumption: The valve stem is the heaviest point on the wheel. That’s why we line it up with the dot on the tire that marks its lightest point. So this is where we are starting – with a set of freshly mounted tires.
While you’ll find a few places on the internet that say you can construct your own perfectly adequate balancing stand, we’re proponents of buying the real thing. This way, you can be certain that your wheels are rotating properly. The stand used here solidly holds the wheel on a rod via a pair of coned, self-centering inserts. (Note: Remove any spacers from the wheel before inserting the rod and cones.) The rod then rotates on two pairs of wheels.
Finding a wheel’s heaviest point is easy. Place the rod on the balancing stand and give the wheel a slight spin. When the wheel stops, the heaviest section of the wheel will settle to the bottom. Although experienced wheel balancers can gauge how much weight to add to the wheel by the speed with which the wheel drops to the heavy point (go to the track and watch the tire vendors sometime), we can usually begin with two quarter-ounce weights. Remove a small portion of the weight’s tape cover and attach the weights to the opposite edge of the rim directly at the top of the wheel.
Turn the wheel a quarter turn so the weight is level with the axle. If you’re close to the correct amount of weight, the wheel should not turn when you let go. If you need to add more weight, the weights you’ve already attached will return to the top of the wheel. You can probably guess that if the weights end up on the bottom, it means you need to remove some. You can trim the weights down to size with a pair of wire cutters. The wheel is balanced when it doesn’t move when it is stopped at random places.
Mark the tire with chalk where the weights are mounted. Pull the weights free and clean the spot with contact cleaner. Remove the rest of the protective backing on the weights and apply them as close to the rim’s center line as possible. For more than half an ounce of weights, split the weight up to either side of the wheel. If you find that you need more than an ounce of weights, check to be sure that the tire is properly mounted. (You did remember to remove the old weights, didn’t you?)
Before you remove the wheel from the balancer, give it one last check. For added security, cover the weights with a piece of duct tape that extends at least an inch beyond the lead weight. If you don’t want to look like a geek, make sure the tape is the same color as the wheels. However, gray duct tape is still better than no tape at all, and mankind almost unanimously agrees that duct tape is one of technology’s greatest achievements.
Your wheel is now ready to be mounted on your bike.