Anti Lock brakes

  ams4127 17:47 19 Dec 2010
Locked

Since its a known fact that antilock brakes are just about useless when driving in snow, is it not strange that vehicle manufacturers do not provide a way to temporarily disable them?

I'm almost sure that when these brakes were first introduced, they were switchable.

Anyone else agree, or am I on my own on this?

  Fruit Bat /\0/\ 17:51 19 Dec 2010

Removing the ABS fuse will disable them

However since ABS only cuts in when wheels lock you are obviously braking too hard in bad conditions.

  Forum Editor 18:01 19 Dec 2010

when driving on snow, but that's not a justification for removing the ABS fuse - that seems to me to be an unwise thing to do.

The function of the ABS is to prevent the car from skidding under emergency braking, but you shouldn't be braking that hard in snowy conditions anyway.The golden rule on snow is to do everything very gently - no fierce acceleration, braking, or changes of direction.

  ams4127 18:33 19 Dec 2010

I never said that I was having trouble, I just posed a theoretical question.

I certainly would not advocate removing a fuse but, if I had an emergency and knew I was going to be driving through deep snow, then I would be happier with a switchable system.

Having spent many happy years at Bruggen and Laarbruch driving cars without ABS I still prefer a car which, in the snow, will behave as I want it to rather than at the whim of some piece of technology.

In almost all other conditions ABS can be a lifesaver and I would never switch it off.

  karmgord 19:13 19 Dec 2010

My 1990 Audi 80 Quattro had such a button, as well as a rear diff lock

In snow & Ice at LOW speed (less than 10mph) locked wheels stop quicker than ABS but you do of course lose your steering.Not much point in old fashioned cadence braking as you might as well have the ABS on as it cadence brakes a million times faster than any human.
Of course modern cars with ESP stability need the ABS working.

  OTT_B 19:28 19 Dec 2010

The are two major reasons why ABS braking is not as efficient in on ice and snow than non-ABS braking.

1. ABS is not 100% efficient. In fact, to be legal (if I remember correctly) it only has to be 85% efficient. Most cars that I've measured have been in the region of 95% - 98%, but there have been some notable exceptions to this. Keep in mind though, that the efficiency is measured on a flooded polished-basalt tile track (or similar low mu surface), which does not represent the same surface as ice or snow - see (2) below

2. When you skid on snow and non compact ice, it builds up a wall of substrate in front of the tyres, this effectively acts as an additional mechanical brake. Use of ABS prevents this from happening.

Why aren't the systems switchable? The risks of not using ABS, even in snow and ice, for the big big big majority of drivers outweigh the benefits. A non ABS skid will quickly send the vehicle out of control, as the car will easily yaw, requiring some adept driving to rectify the situation. ABS won't eliminate this, but it certainly helps.

A lot of new cars (and all new cars from (2014?)) require ESP (Electronic Stability Programming) which help to prevent yaw build up. ESP is a function of the ABS modulator, so disabling the ABS will also mean that you lose the extra stability controls.

So, yes you can pull the ABS fuse to get better braking, but your driving style will have to change and you will need to know you are capable of handling the vehicle - those of you who were driving in bad weather before the days of ABS are in a better position to do this, but I still really wouldn't recommend it.

So, is it better to stop by not putting your foot so hard on the pedal as the ABS modulates, or just to allow the ABS to do its job?
Answer? No contest: Brake gently. Very gently.

Fruit Bat /\0/\: "Having been able to stop on a very icy incline thanks to the ABS I wouldn't be without them."

That wasn't your ABS helping you. You may just have got lucky.

  morddwyd 19:32 19 Dec 2010

"I still prefer a car which, in the snow, will behave as I want it to rather than at the whim of some piece of technology."

Better remove the Engine Management System fuse as well them!

  ams4127 19:50 19 Dec 2010

Ah yes, and return to the good old days of setting the points and turning the distributer until the engine runs best....Ah No!!!!!

  karmgord 19:51 19 Dec 2010

Removing the ABS fuse would definitely invalidate your insurance should it come to light after a accident.
Try to slowing down by changing down gear using the reverse torque of the engine to slow you down.
Bottom line is in snow & ice drive EXTREMELY SLOWLY and leave a LARGE "braking" distance.
When pulling away use as high a gear as the engine can manage,second or third,gentle with the throttle.

  Monoux 19:57 19 Dec 2010

OTT_B--

"Fruit Bat /\0/\: "Having been able to stop on a very icy incline thanks to the ABS I wouldn't be without them."

It was fourm member who posted those words not
Fruit Bat /\0/\

  OTT_B 20:02 19 Dec 2010

Absolutely right.

This thread is now locked and can not be replied to.

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