Strange how the ABS works.

[Mike Noc]

Had the front wheels jacked off the ground today, and blocked of course, to look at why my car knocks on drive take up.

So went for another 'virtual' drive (have done this before but wanted to be sure of the result), got up to 70 mph in fifth gear with the rear wheels stationary and strangely no ABS alarm. Braked a few times and still nothing.

I know on some of our cars the ABS light does come on doing this, but has anybody else tried it and had no alarm lights?

The ABS system works perfectly on my car, and has alarmed in the past when a single sensor has failed to read wheel rotation.

So did Rover build in an allowance to do handbrake turns without bringing up any alarms, or is there another explanation? :shrug:

[mantianak]

I don't know for sure but I'm guessing it kicks in when the it registers changing of different speeds. And perhaps some kind of tolerances programmed in, like when you corner. So if one set of wheels hasn't moved at all it knows it. Like I said, that's a guess and not a definitive answer so don't hold me to that!

[Jakg]

Having driven at speed with the rear wheels not moving (rolling road), yes the ABS light did come on.

[neilbaker86]

It's probably designed to not give a warning in those circumstances because when your car is having a brake efficiency test on an MOT, one axle is tested at a time, and the wheels on the other axle are stationary.