Measure of the longitudinal force coefficient

Griptester is a Findlay Irvine vehicle which will be used for the following application:

  • The measure of a longitudinal force coefficient (LFC) between the overlaying and a tyre based on the principle of a braked wheel with a constant slip rate of about 15%. This slip rate, which generates the skid resistance, is obtained by mechanical drive between the two carrier wheels and the measure wheel.
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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.

  • Length: 1,010 mm
  • Width: 790 mm
  • Height: 510 mm
  • Weight : 85 kg
  • Measuring tire: Diam. 10”, smooth wheel track (ASTM Specification 1844 – Findlay Irvine)
  • Traction wheel: Diam. 10”, Dunlop type 10 x 3.6-5

Download the GRIPTESTER datasheet in PDF format

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