The axis of the measure wheel is equipped with a system of stress gauges allowing the measurement of the reaction of the soil on the tyre, Vertical Force (VF) and Horizontal Force (HF).
The longitudinal force coefficient measured by the GripTester, called GN, is proportional to the ratio of HF to VF.
The measure is taken on a wet surface. The longitudinal force coefficient calculated by the GripTester is displayed in real time and stored on a laptop.
Use in towed mode (roads and motorways) for continuous skid resistance evaluation.
The measure is performed at a speed depending on the evenness of the carriageway.
For wetting, an internal tank is added to the towing vehicle to increase the measure of autonomy.