Wheel balancing is a separate issue from wheel alignment, with different adjustments and measurements, as well as different symptoms for wheels that are out of balance. Essentially, when a car’s wheels are correctly balanced they will rotate with vibration. The simple explanation of wheel balancing includes reference to spots on the wheel and/or tire that are heavier than the rest of the wheel. The mechanic or service person usually places a lead weight on the side of the wheel opposite to the heavier spot, to balance out the weight.
In contrast, wheel alignment has to do with angles, whether the wheel is perfectly parallel, toes in or angles in or out at the top, for example. This may also cause some wobbling or vibration but it is different from the effects of wheels that are out of balance. Most of the time, a service person looking for problems with alignment will look for unusual wear on the tire. The driver will have difficulty keeping the car traveling in a straight line.
When car wheels are not properly balanced, there will be vibration when the car is driven at a higher speed on the open road. This often occurs when the car reaches approximately 50 miles per hour but can also be noticeable at 60 or 70 mph. Passengers may also feel this vibration through the floor of the car or even through the seat. Tires will wear improperly when out of balance as well, but this shows up with cupping or concave wear.
According to most technical and service information, even an ounce of extra weight on one side of the wheel can lead to significant vibration. In recent years, service personnel use a specially designed machine that turns the tire at a high rate (spins). This locates any heavy spots on the outer edge of the wheel. That is when a lead weight can be attached on the side opposite the offending spot. Sometimes, less-expensive tires will lose balance and cause symptoms similar to unbalanced wheels. Buying better tires is one way to avoid this problem that is associated with wheel balance problems.
Wheels can be balanced while they are on the vehicle or they can be balanced with shop machinery, as mentioned earlier. Technical information on wheel balancing, wheel alignment, tire care and other related subjects lists the types of balancing procedures as “static” and “dynamic.” Static balancing takes place when the wheel and tire are still. A bubble-balance procedure is used for this method.
Dynamic balancing is the method that spins the tire and wheel. New technology allows service personnel to use a computer-readout style of balancer. This method indicates places where the wheel is heavier and indicates where to place weight to compensate. The common balancing weight is made of lead and is tightly pressed or clipped onto the wheel. While these have been in common use for years with steel wheels, some of the new alloy and designer-style rims don’t work well with the rough lead weight. There are new types of weights that attach with an adhesive, which may eliminate scarring and scratching.