Road Force Balancing
An advanced wheel balancing technique that applies a roller load to simulate the weight of the vehicle on the road.
Road force balancing is an advanced method of balancing a wheel and tire assembly that goes beyond traditional spin balancing. A standard spin balancer only measures static and dynamic weight imbalances; a road force balancer uses a heavy load roller to press against the tire, simulating the weight of the vehicle on the road.
As the wheel spins under load, the machine measures tire radial force variation (stiffness changes) and rim runout (bent wheels). It can identify hidden defects like a soft spot in the tire sidewall or a slight dent in the alloy wheel rim that causes a vibration, even if the wheel is perfectly balanced in terms of weight. The machine's software can instruct the technician to rotate the tire on the rim (force matching) to align the stiffest part of the tire with the lowest spot on the wheel, canceling out vibrations.
If a driver experiences a persistent steering wheel vibration at highway speeds that standard balancing cannot resolve, road force balancing is recommended. It is also used when mounting low-profile tires or high-performance wheel packages. Mechanics use this diagnostic tool to locate defective tires with excessive internal construction irregularities before they cause customer complaints.