driving test and brakes 554

Heh! :)

I don't know of any car where one cannot lock up at least one wheel. But locking up a rear wheel in a Ka without ABS, or triggering the ABS if it has it, is only done if you have shot front brakes, or if you're descending a steep gradient and you brake firmly.

Yes. Also until the advent of electronics or sophisticated (and therefore expensive and potentially unreliable) mechanical devices to automatically control the rear braking effort according to load and conditions, the last thing anybody sane wants is a locked rear wheel under emergency braking. If the braking effort were split closer to fifty fifty, you may have a locking rear wheel all too often.

As I understand it, many cars without electronic brake force distribution have a relatively primative load sensing sensor somewhere in the back that increases rear brake effort when the car is relatively heavily laden.

Yup, unless you've locked a rear wheel or two and the road camber slews them to the side...

Hmm. Yes, but no worse than a non-ABS system.

ABS systems work by detecting the sudden deceleration just *before* the wheel stops turning. They then momentarily release the brakes and the system repeats. Some systems have a brief period of the wheel nearly or footprint of the Ka's ABS on snow. Also have a look at the video here: www.dervman.com-kermitabsonsnow.MOV This shows the wheels momentarily nearly locking on a very slippery surface. On a less than sheet ice :) surface you retain some steering effort... but of course the steering ability of the car under heavy braking is limited anyway.

I do see your point, however, it's more a case of driving within the abilities of the car road tyres whatever. I've wanted ABS on my cars but never actually *needed* it or thought to myself, "phew, thank God I have ABS." In proper wintery conditions it can be a pain, www.dervman.com-ttwg.htm as an example.

End it? It's a useful discussion... :p

-- The DervMan www.dervman.com