Why Are Modern Car Brakes So Sharp?

[welshpug 1,622]

I loved the steering of my mate's CX Safari, I was expecting something totally different to the 205 but still very french, I loved it.

 

shame he sold it could have done with borrowing it again to move house

[cybernck 400 1 Cars]

i have a few friends that always slam the brakes on snow to activate ABS

and when i ask them why the heck do they do that when can they brake

normally and still stop without problems, they respond "why have ABS

if you don't use it" .

[osama 0]

on a pushbike...(similar principle) less powerful brakes are always so much sharper...i am unsure why but a 6 pot brake almost needs to bite, grip in, hold it and then lock. Whereas a cheaper hydraulic disc locks almost instantly..but suffers at high temperatures!

[jackherer 543]

And the steering?

 

That worries me

 

There is a mechanical failsafe, you feel it when the engine is off, the wheel has a degree or two of free play then hits a metal stop and starts to turn the wheels.

[Henry Yorke 269 3 Cars]

I love the brakes on my 307 HDI as they feel superb, however you really notice it if you roll the car down a hill with the engine off and try and stop it on the pedal. With a 205 it is alright to do that. Basically in a 307 if your servo fails you are not stopping, in a 205 you may try the 2 footted approach and get away with it.

[pug_ham 240 3 Cars]

i have a few friends that always slam the brakes on snow to activate ABS

and when i ask them why the heck do they do that when can they brake

normally and still stop without problems, they respond "why have ABS

if you don't use it" .

I thought snow & ice fooled abs so the car locked up still? It certainly fooled the ABS on a Chavalier I hired ages ago when I was hooning it round a snow covered carpark in Malham one Christmas. We got the car to kangaroo with some left foot braking.

 

Modern car brakes are certainly over servoed in general, at least all the ones I've driven have been on cars less than five years old. It can be interesting when a relatively new car (<five y/o) is following me in my STDT or GTi & I brake last minute for a different speed limit zone, two or three times recently the car following has swerved to the middle of the road because I slowed much faster than they expected.

 

But then this is the way with modern cars, take the driving away from the driver & let the electronics control the car more.

 

Graham.

[Sandy 189]

Didn't early Quattros have an ABS off button for snow and gravel, because you can stop quicker without it?

[welshpug 1,622]

on the subject of snow and ABS a friend told me last week of an advert for the ford sierra, which consisted of a dual carriageway with one clear lane, the other lane with a few inches of snow.

 

Cue sierra driven along straddling the snow+clear lane @ 70mph, then lamping on the brakes, and it pulled up in a straight line.

 

 

one I've heard many times, a car will STOP quicker without abs on snow, if controlled well...

[Paintguy 0]

Didn't early Quattros have an ABS off button for snow and gravel, because you can stop quicker without it?

Yes iirc. On extremely bad winter surfaces, the locked wheel could build up a little 'ramp' of snow in front of it, helping to slow the car down.

 

Matt - if you think an Astra stops well, you want to try a new shape Megane! I used to jump out of my 205 to drive Zoe's old one, and it was only the seatbelt locking on that stopped me head-butting the steering wheel.

 

As said, most modern cars simply have too much assistance, to help those too feeble to press the pedal hard enough And as Henry points out, it also makes the brakes extremely ineffective if the servo packs up.

Edited January 5, 2008 by Paintguy

[Tom Fenton 1,525]

Didn't early Quattros have an ABS off button for snow and gravel, because you can stop quicker without it?

 

Yes they did, in fact all the UR quattros have it, my Dad has a late 20v one and that has it. They also have an accelerometer under the rear seats so they can detect the car moving if all 4 wheels are locked under braking on ice etc so as to unlock one or more as required.

[Nathan 0]

Didn't early Quattros have an ABS off button for snow and gravel, because you can stop quicker without it?

 

My old cav had a similar switch that I used to use when it was really snowy or icey (well it wasn't really a switch, I just used to pull the ABS fuse out!)

[tom_m 0]

I love the brakes on my 307 HDI as they feel superb, however you really notice it if you roll the car down a hill with the engine off and try and stop it on the pedal. With a 205 it is alright to do that. Basically in a 307 if your servo fails you are not stopping, in a 205 you may try the 2 footted approach and get away with it.

 

whereas the other way round 307 brakes one the 205 without a servo stops quite nicely (albeit with a bit more effort than usual)

[saveloy 8]

With regards to the Audi Quattro, it wasn't an ABS 'off' button, but a locking centre diff 'off' button. That was there because in icy/snowy weather a locked front wheel would also lock the rear brakes.

[snillet 1]

I am not shure about new cars TODAY cause the manufacturers of the ABS equipment tells that the systems are much quicker today and should be able to stop more efficiently then a "human foot". But up to just a few years ago a skilled human could stop a LOT quicker on for example snow/ice without the ABS.

 

Thing with ABS though is that it´s supposed to help in panic situations, when doing a test on it you´re prepared for when to brake and all that, in jamed traffic and bad weather that´s not the same really.

[blackscooby 0]

With regards to the Audi Quattro, it wasn't an ABS 'off' button, but a locking centre diff 'off' button. That was there because in icy/snowy weather a locked front wheel would also lock the rear brakes.

 

Mine definitely had an ABS button as well as the diff locks. (1984 ur Quattro)

[de Noir 0]

I tried to fit larger 255mm diameter servo, thought of mating it with 22 or 23,8mm mbc.

Unfortunately, left hand drive 205 engine bay-pedal combo does not accomodate anything larger than stock 225mm servo.

Edited January 8, 2008 by MH_

[Tom Fenton 1,525]

With regards to the Audi Quattro, it wasn't an ABS 'off' button, but a locking centre diff 'off' button. That was there because in icy/snowy weather a locked front wheel would also lock the rear brakes.

 

Incorrect I am afraid. The early cars could have both centre and rear diffs locked manually using a pneumatic system, at whatever speed you desired. The later cars had a torsen torque biasing centre diff, and allowed you to lock the rear diff, but only at slow speeds up to 25km/h, using an electronic system. Over that speed setting the electronics would unlock the diff. In normal setting (e.g. knob not pulled out early car, button not pressed later car the diffs are unlocked). Locking both rear and centre diffs on the early cars when on tarmac makes them drive horribly!

Both the early and late cars had a button marked "ABS AUF", the manual for the car describing this as disabling the ABS system in ice and snow.

 

My father first owned a very early (non-digital dash) 10v ur Quattro in about 1986, in about 1993 he bought one of the last 20v ur Quattros, he still has both cars, and keeps threatening to cut the 10v in half to shorten it as per the Sport Quattros.

Hence my knowledge of these cars, I was 6 years old and a car nut, so when my Dad came home with an Audi Quattro I naturally thought it was the best thing since sliced bread. In fact I even remember being very confused and disappointed when we went to watch the BTCC in about 1989, as I said to my Dad "Your quattro would be faster than those wouldn't it Dad" and the response came back "No!" to which I said "But they have no turbo!".

[paulh 0]

and keeps threatening to cut the 10v in half to shorten it as per the Sport Quattros.

It's got to be done - saw one at a trackday last year at Elvington in the old works colours - looked awesome

[Rippthrough 98]

My father first owned a very early (non-digital dash) 10v ur Quattro in about 1986, in about 1993 he bought one of the last 20v ur Quattros, he still has both cars, and keeps threatening to cut the 10v in half to shorten it as per the Sport Quattros.

 

 

I like your dad already

[Tom Fenton 1,525]

He is not bad for an old git. In his spare time he likes to go autograss racing in a twin motorbike engined Yaris. He has also been known to go sideways around roundabouts in the snow in his Merc Atego (7.5T lorry).

 

In fact here is a picture of the 20v-http://s12.photobucket.com/albums/a221/tom...nt=Quattro1.jpg

Edited January 7, 2008 by Tom Fenton

[saveloy 8]

Tom, I thought the button was to lock the centre diff. Hence my reasoning.

Locking both the front and rear diff would simply lock each individual axle, but not lock both axles together.

[Tom Fenton 1,525]

You cannot lock the front diff, in fact I've never known anything in which you can lock the front diff, it would make turning impossible. You can lock the centre diff. But there is an ABS off button which is completely seperate from the diff lock/s.

[Dream Weaver 2]

It's not just old vs new either it can be the other way round.

 

I thought the brakes on my dads old 92 K plate 405 SRI were superb, compared to my 1.6 GTI I had just after driving the 405 for a year.

 

The brakes on my current Civic are under servod if anything as you have to give them a bit of a push to get it to stop and I preferred the 405 brakes - in fact the brakes on the 205 and civic are very similar, and I don't particularly like either of them especially compared with the 405

 

I may be getting old and lazy, but a brake pedal that stops you without much drama/effort is something which is attractive to me. I'm thinking of buying a Focus ST at the mo (sorry 205 you may have to go ) and that has MEGA brakes from the test drives I've done so far.

[C_W 3 1 Cars]

My girlfirend's 52-reg clio has the exact same girling calipers as the 1.9 with 260mm discs and they feel very good at high speeds, more powerful than the 205 by initial "feel" so it must be the larger/better servo.

[jackherer 543]

IIRC right hand drive 205 GTIs use a smaller servo than LHD 205 GTIs so maybe the LHDs are more like modern cars?