: In fact I've never seen them alter anything when doing the : brake test in the past - they just press the buttons to operate the : rollers.
The readings are taken in kgf then entered into the computer, which works out whether it passes by comparing with the vehicle weight. My last tester had great difficukty finding the unladen weight of a 2CV. Apparently the VOSA system does not accept "two fifths of bugger all" as a valid value.
Ian