Tire Force Variation Check

Tire stiffness variation, or loaded radial runout can also cause a vibration. However, this is difficult to measure without a tire problem detector or a loaded radial runout buffer. The tire problem detector is simply a roller drum that slowly rotates the tire, while under load, (mounted on the vehicle) measuring spindle movement. The loaded radial runout buffer is a more automated machine that slowly rotates the tire under load with a roller drum off the vehicle and measures the tire's stiffness. It will then "match" the tire to the wheel by buffing off small amounts of rubber from the outer tread rows at the stiff spot. This procedure is usually effective, especially when used as a measuring device and for fine buffing only. This equipment requires careful use. Do not remove too much rubber. Because this equipment is not always available, the most basic procedure of measuring free runout with a dial indicator, as previously detailed, is usually more practical. The free runout of the tire will usually correspond with the tire's stiff spot.