Description
The GripTester measures a longitudinal friction coefficient (CFL) between the surface of the road and a tire with a braked wheel with a constant slip rate of about 15% close to the optimum of the anti-blocking system. This slip rate, which generates the adhesion force, is obtained by mechanical drive between the two carrier wheels and the measuring wheel.
The axis of the measuring wheel is equipped with a system of strain gauges to measure the reaction of the ground on the tire, Vertical Force (FV) and Force Horizontal (FH).
The longitudinal friction coefficient measured by the GripTester, called GN, is proportional to the ratio FH on FV. The measurement is carried out on a wet surface. The longitudinal friction coefficient calculated by the GripTester is displayed in real time and stored on a laptop. It can be used in towed mode (roads and highways) for a continuous evaluation of the adhesion. The measurement is carried out at a speed dependent on the road surface. For wetting, an internal reservoir can be added to the tractor vehicle in order to increase the measuring range.
