A mobile tire test apparatus was built to evaluate tractive performance of off-road traction tires under field conditions. The tire test machine was designed to test tire sizes up to 18.4-38, with static loads of 24.5 kN or less, tractive forces up to 18 kN and actual velocities less than 8.5 km/h. The tire test machine was operated with the test tire pulling the tractor rearward. The operator controlled speed of the tractor and test wheel to obtain the desired level of slip and velocity.
