ABS

[Jon1967x]

I've made a point on a different thread because its my experience but I'd welcome the views here.

I think we'd all recognise the value ABS has in retaining control of a car under heavy braking when the wheels would lock up.

But is it the quickest way to stop?

Some (including Bosch) claim it is, however I believe that braking just shy of the ABS kicking in is quicker, and if ABS starts to kick in (especially on compacted snow, but also in rain and other situations where grip is low) easing off the brake a little to reduce the ABS activation stops the car more quickly. It certainly seemed to be that way when I had a day at Millbrook and spent some time in the brake test area.

Thoughts?

[Jon1967x]

GravelBen said:

It depends a lot on the particular system - most of the comments about how amazing they are etc are based on latest generations systems in relatively expensive cars, I don't know if lower budget new systems are as good and I do know for a fact that 5-10 year old systems can get very confused in some situations.

It depends on the surface as well - on a smooth mixed-grip surface the individual wheel braking is a big advantage, on loose gravel or snow they don't do so well.

Its hard to generalise really - with 10 year old ABS on corrugated gravel I can stop the car quicker (and control it more easily) with the handbrake but I wouldn't expect to beat a recent system on partially ice tarmac.

From my experience, and its probably only practical to implement on fairly low grip surfaces like very wet roads, compacted snow, greasy roads etc, that if you over power the brakes massively such that the ABS is working hard for more than a few pulses, it can be quicker to stop by avoiding the ABS kicking in. I had the good fortune to do this on the brake test section of Millbrook in an Aston Martin - checkerboard road surface drenched in water and you could stop 1-2 car lengths quicker than stomping on the brakes by feeling for the lock up point. I've known it on compacted snow where a friend who lived in Norway for a few years advised very gentle braking as the ABS would simply pulse on and off and couldn't modulate the break pressure enough to cause effective braking. My daily driver is a new shape BMW 6 series so I imagine the brakes are up there with the latest technology (at least in terms of what most cars on the road have) and its the same with that. Tarmac, dry road, warm tyres, you've no chance of beating the ABS. Slippy road where the car just doesn't seem to want to stop, its worth trying less pressure.

I thought others may have experienced this but seemingly not. There's lots of comments on ABS v non ABS around, but very little on ABS kicking in and ABS not quite kicking in.