The Grip Tester is a surface friction tester which may be towed at speeds up to 130kph or pushed at a walking pace. It works on the braked wheel principle and the towing arrangement is such that the nearside wheel path, offside wheel path or oil lane can be surveyed independently.

On highways, a Grip Tester survey is normally carried out at 50kph using a towing vehicle capable of depositing 18 litres of water per minute in front of the measuring wheel. Drag and load are continuously measured and their quotient - the friction coefficient - is collected, processed and displayed on a computer carried in the cab of the vehicle.

During the survey, identifying features are recorded by the operator who can also monitor the Grip Number, chainage and speed. Immediately after the survey, average Grip Numbers and a trace of all or part of the survey can be examined, the events edited and a report produced results can be converted to equivalent SCRIM SFC and tailored to meet your individual requirements.