Rock knocker
Veteran Member
Yeah, I have no idea if they are linear. Guess one would have to come up with a sensor of some type that would allow for the measuring the rpm of the pto shaft at a couple of different engine rpm levels..
Loss of power in a HST or other torque converter, or other secondary parallel transmissions notwithstanding, PTO rpm and engine rpm should always have a linear relationship in live and most independent PTO's