Coefficient of Friction Testing

[kramarczyk]

Originally Posted by IKE

Back to how accurrate does it need to be, within the measuring technique you showcase, If your angle accuracy is accurate to within +/-1 degree, at 45 degrees, you will come up with a CoF of 0.966 to 1.036. Or a total error band of about 7%. +/-2 degrees will get you 0.93 to 1.07. In terms of FRC wheels, that would be pneumatics fully inflated (according to AM wbsite) to fresh wedgetop. My phone has an inclinometer app on it that measures within 0.1 degrees, but on a flat surface, with me holding it steady, it varies +/-0.7 degrees.

Do you guys actually measure the angle and then do the trig? Wouldn't measuring the rise over run with a carpenters square provide better resolution. Rise / run = tan theta = CoF

An 1/8" difference in rise is pretty easy to measure and works out to ~ 1% change in CoF.
12/18 = 0.66667, 12.125/18 = 0.67361, 1.03% difference
17/12 = 1.41667, 17.125/12 = 1.42708, 0.73% difference