[Power Surge]

Road force basically measures how out of round the wheel assembly is. First you measure the spinning tire, which measures the assembly. Then you use the sensor arms to measure the rim itself (while still on the tire). If you have high spots and low spot in both the tire and rim, the machine will tell you where to spin the tire on the rim so that the high spots and low spots cancel each other out, giving you the least amount of overall runout.

Typically we consider 15 and under acceptable for a car wheel. 33 is very high. I had huge shaking issues with my Cobra wheels and after I took the car to work and road force balanced the wheels, it was like a whole new car.