ABS ... have you ever used it ?

[Nigel Worc's]

As the title says really.

Apart from messing about (kof , sorry, self training), it's just something that has been on my cars for a long time now.

Being an older type, I've always been taught cadence braking, and I'd sort of worried that in an emergency I'd ease off the brakes when the abs cut in ..... in a live situation.

but ..... I didn't, and it was absolutely bloody fantastic.

A stag "appeared" in front of me last week on a remote scottish highlands road, it was dark (read pitch black), no road markings, no cats eyes, speed was towards the limit, but certainly not exceeding it.

I was aware that the situation could arise, but I'll admit I was totally caught out by how quickly that bloody great animal could get itself in front of me !

Anyway, I missed it, but I think it was down to luck and abs, rather than any driving "skill" on my part.

[militantmandy]

I've locked the wheels in a car with ABS in the wet and surprised myself by how quick my counter steer reaction was! I've also been saved by the abs when my heavy foot would probably have ended with me sliding into the back of a car at the end of queue at temp lights. Have avoided animals in the road before, but not really needed to brake hard, more just steer quickly! In an ideal worl we'd all be able to perfectly cadence brake, but it's bloody good to know the abs is there!

[shakotan]

I'd just bought my first 'quick' car, an Audi A8 4.2.

Was 'proceeding' down a long straight road past an Industrial Estate, a 30mph limit, but I was doing about *cough* 45 leptons *cough* when I saw a Mercedes approaching from a side road to the right.

Realised there was a very poorly marked mini roundabout at the junction, and Mr Mercedes was - quite rightly - going to pull straight into my path.

Ooh, THAT'S what ABS feels like then!

[driverrob]

I deliberately 'used' mine several times last winter. Every time I went out on the snow I braked gently at low speed to get a feel for how slippery the surface had been made by traffic.

[xr287]

Only used it on the road in my current car once just to check it was working.

Had it on my mini racing car so used it almost every time I braked, used to burn out sensors fairly regularly!

[nobodyknows]

never, which is why driving my 172 Cup that doesn't have it doesn't bother me at all. Better to have it & not need it than to need it & not have it though I guess.

[StevenJJ]

Yes; the last incident of which it definitely prevented an accident.

Night-time on a was-wet-now-drying-and-greasy Manchester back road, car loaded up with goodies from Costco and passengers onboard (heavy) a young buck defied the laws of physics and 'came out of nowhere' attempting a three-pointer in the road.

I kept my foot hard in it and stopped with about 6-8 inches to spare and given the conditions and irregular loading of my car (it's usually just me and no extra weight) I could not have done a better job save for maybe ten attempts prior to get the feel of it all... which one doesn't get on the road

[PeteG]

Going up the A1 on Friday, lane 1 fairly heavily trafficked, lane 2 was practically empty. Waited for a van to pass me, stuck my signal on, moved out - just as something pulled clean in front of the van - van does a hard stop, I stood on the anchors and left some sweat off my forehead on his rear bumper. Close one.

[FunkyNige]

I'm afraid even after doing a young driver's day on the skid pan back when I passed my test learning how to cadence brake, when it comes to an emergency in my ABS equipped car I just tend to push the brake pedal through the bulkhead and aim for something soft
Only happens once or twice a year though, and like a poster above I try and get ABS to kick in when it snows to see how much grip there is.

[GravelBen]

I don't recall ever having had to rely on it to stop or avoid something - in fact the situations where its activated most (mainly gravel, sometimes snow) I've often had to drive around it to prevent an accident, as those are the situations its worst at dealing with.

Thats not to say I wouldn't take advantage of it if something large and solid suddenly appeared in front of me on a sealed road though, especially on a wet surface.

Edited by GravelBen on Monday 30th August 13:34

[Mastodon2]

My car does not have ABS, but I have never locked the wheels in the wet or in the dry. I've deliberately locked them in the snow as mentioned earlier, to see how hard I could apply them before the car would lock up. Useful learning tool I think, you don't realise how easy it is to lock wheels / provoke ABS until you do it deliberately at low speeds in a safe place. Then when I see people driving fast in high risk areas when the snow is piled up, I think "If you hit the brakes now, would the almost inevitable accident be bad, terrible or catastrophic?"

[topless_mx5]

In my old Rover 200Vi and Mondeo ST24 it got used regularly. When pressing on a bit the ABS would kick in far earlier than required, which was very frustrating.
In the MX5 with no ABS I am much happier, never locked a wheel even when using the brakes hard.

[Wolands Advocate]

I was actually intrigued to note that yesterday, when I had to absolutely stand on the brakes at about 60mph having rounded a country bend to discover a pheasant standing gormlessly in the middle of my lane (there was a Discovery coming the other way so swerving not an option), that the car stood on its nose and came to a total halt in very short order without so much as a peep from the ABS. Mr Pheasant lived to see another day and more importantly didn't expensively clout the front of the car.

Now I know the car has pretty beefy 6-pot calipers and the road was dry but I was still mildly surprised. I'm presuming it's tyre-related - i.e. provided the tyres keep grip, the ABS won't trigger?

[xr287]

Wolands Advocate said:

I was actually intrigued to note that yesterday, when I had to absolutely stand on the brakes at about 60mph having rounded a country bend to discover a pheasant standing gormlessly in the middle of my lane (there was a Discovery coming the other way so swerving not an option), that the car stood on its nose and came to a total halt in very short order without so much as a peep from the ABS. Mr Pheasant lived to see another day and more importantly didn't expensively clout the front of the car.

Now I know the car has pretty beefy 6-pot calipers and the road was dry but I was still mildly surprised. I'm presuming it's tyre-related - i.e. provided the tyres keep grip, the ABS won't trigger?

Doesn't matter what size your brakes are, braking force is limited to tyre on road friction. You must have decent tyres or been on a fairly rough and high friction road surface. So yes as long as your tyres have enough grip to keep rotating while decelrating ABS has no reason to interfere.

[HereBeMonsters]

xr287 said:

Wolands Advocate said:

I was actually intrigued to note that yesterday, when I had to absolutely stand on the brakes at about 60mph having rounded a country bend to discover a pheasant standing gormlessly in the middle of my lane (there was a Discovery coming the other way so swerving not an option), that the car stood on its nose and came to a total halt in very short order without so much as a peep from the ABS. Mr Pheasant lived to see another day and more importantly didn't expensively clout the front of the car.

Now I know the car has pretty beefy 6-pot calipers and the road was dry but I was still mildly surprised. I'm presuming it's tyre-related - i.e. provided the tyres keep grip, the ABS won't trigger?

Doesn't matter what size your brakes are, braking force is limited to tyre on road friction. You must have decent tyres or been on a fairly rough and high friction road surface. So yes as long as your tyres have enough grip to keep rotating while decelrating ABS has no reason to interfere.

But bigger (and better) brakes are able to apply more force without locking up.

I had to use ABS on a recent Mazda experience day. Road looked like it went straight on, but it was a 90 degree right, and I was doing more speed than was really necessary.

[touching cloth]

HereBeMonsters said:

But bigger (and better) brakes are able to apply more force without locking up.

.

I stand to be corrected but can't see how brakes can simultaneously apply more force yet also lessen the chance of locking up. It surely comes down to total frictional force that the brakes can apply between pad and disc, then that traded against frictional grip between tyre and road - It matters not to the tyre/road how that friction at the brakes was achieved. Lovely strong brakes and a set of race slicks in the dry and you'll stop on sixpence, same brakes and a set of ditchfinders you won't.

[HereBeMonsters]

touching cloth said:

HereBeMonsters said:

But bigger (and better) brakes are able to apply more force without locking up.

.

I stand to be corrected but can't see how brakes can simultaneously apply more force yet also lessen the chance of locking up. It surely comes down to total frictional force that the brakes can apply between pad and disc, then that traded against frictional grip between tyre and road - It matters not to the tyre/road how that friction at the brakes was achieved. Lovely strong brakes and a set of race slicks in the dry and you'll stop on sixpence, same brakes and a set of ditchfinders you won't.

It's all to do with how brakes work. You're converting kinetic energy into heat. Much better to do that over a larger area which can transfer more energy into the larger disc (which can in turn dissapate more heat to the air) than a small one. Otherwise all race cars would just have tiny but strong single piston brakes.

[touching cloth]

HereBeMonsters said:

touching cloth said:

HereBeMonsters said:

But bigger (and better) brakes are able to apply more force without locking up.

.

I stand to be corrected but can't see how brakes can simultaneously apply more force yet also lessen the chance of locking up. It surely comes down to total frictional force that the brakes can apply between pad and disc, then that traded against frictional grip between tyre and road - It matters not to the tyre/road how that friction at the brakes was achieved. Lovely strong brakes and a set of race slicks in the dry and you'll stop on sixpence, same brakes and a set of ditchfinders you won't.

It's all to do with how brakes work. You're converting kinetic energy into heat. Much better to do that over a larger area which can transfer more energy into the larger disc (which can in turn dissapate more heat to the air) than a small one. Otherwise all race cars would just have tiny but strong single piston brakes.

The tyre/road grip combo couldn't surely give two hoots how the braking force is created be it 6 pot, 4 pot or rubbing your todger against the spokes of the wheel - if the brakes are strong enough to overcome the grip between road and tyre then they'll lock, if not they won't. I do understand how 6 pots are "better" and have many benefits including better heat characteristics (barely relevant in single hard stop situation, far more important where repeat braking is required as in a race car), what I take issue with is the assertion that 6pots can simultaneously provide stronger stopping force and yet be less susceptible to locking the wheels.

[itsnotarace]

HereBeMonsters said:

It's all to do with how brakes work. You're converting kinetic energy into heat. Much better to do that over a larger area which can transfer more energy into the larger disc (which can in turn dissapate more heat to the air) than a small one. Otherwise all race cars would just have tiny but strong single piston brakes.

Heat dissipation is only relevant in repeated heavy stops from high speed. Have a read of this:

http://www.stoptech.com/tech_info/wp_brakesystems_...

In fact, all of the whitepapers on the Stoptech site are worth reading.

http://www.stoptech.com/tech_info/tech_white_paper...

[MadRob6]

In my first ABS fitted car (an 93 XR3i) it was pretty easy to get the ABS to kick in and living down a narrow country lane filled with nutters meant it was a common occurence as the ABS kicked in at the slightest hint of an emergency stop. Second car was a VW which didn't come in nearly as quickly despite the brakes being used in anger quite often due to country lane, corner, oncoming car combinations.

Current car which is another (but 10 years newer) VW and don't think I've had the ABS kick in on me once which either means I've calmed down on the roads or the systems have changed a bit. Moving back to a non ABS car in the near future so will have to try and remember that.