I find that the ABS systems fitted to cars (and other vehicles - the following was actually conducted in a van) now are too sensitive to promote decent braking, but I have been experimenting the last few days with an alternative which seems to be reasonably effective; select a low-ish gear relative to the vehicle speed (probably 1st or 2nd gear), then ease the clutch out and use the clutch as the brake pedal to control the engine braking (from idle) being applied to the wheels (i.e., slowly release to the bite point but then feather it at that point to control the amount of engine braking). There is no interference from the ABS and it does seem to be relatively effective, although if used a bit too aggressively then it causes the front wheels to wash out (as they're sliding relative to the road), but this is easily remedied by easing the clutch back in a touch. If 2nd gear was used initially, once engine speeds in that gear get too low to provide effective braking, then slotting into 1st to bring the car virtually to a stop.

What do the experienced winter motorists think to this idea?

Not an experienced winter motorist, nor an expert on cars but I've always been told off for using my gearbox to slow down. Always been told it not good for gears. Cant be that good for clutch either I would presume.

I don't know.

If you've got 4 tyres contacting the road, and pressing the brake pedal gives you 4 contact patches trying to slow you down. If you then switch to only using the 2 driven wheels to slow you down, half of the braking ability is cut out the equation.

You are cutting abs out of the equation, so you'll probably stop a bit quicker on snow because the driven wheels will dig into the snow if they're locked up, but like you mentioned you loose all steering (on a FWD) while that's happening.

To try and cut the cost a bit, you could rev match to eliminate wear on the clutch and just use engine braking, but if the retardation from the engine is too much for the grip available, you're back to dipping the clutch to get control back.

I don't think this ones for me :-( Softer on the footbrake would be my bet i think, use ABS cutting in as a sign to tell me i've done it wrong.

Interesting topic. I'm no advanced driver but I do enjoy "exploring" in the snow.

I agree that ABS can increase the stopping distance in snow. Experimenting by reversing very slowly in a straight line, I found the handbrake stopped the car considerably quicker than the footbrake (because, as you said, it builds little wedges of snow behind the rear wheels), but this isn't something to try going forwards or you end up sideways.

I've found the safest way to slow in snow is to avoid braking altogether, as far as possible. I try to plan as far ahead as I can and slow down by lifting my foot off the accelerator.

When going down hills that would otherwise cause the car to run away, I agree that using engine braking in a low gear seems to give better control than using the footbrake in a higher gear. I'm not sure about letting the clutch out from idle, though. I think if I had to change down "unusually" early, I'd rather raise the revs to match the road speed before declutching, so as to reduce wear to the clutch plates and avoid a jerk that could induce a skid.

Will is correct; ABS will not stop you faster in deep fresh snow (several inches, say at least 2), or on similar depth loose gravel, because the snowplough effect of locked wheels makes them dig into the soft surface. OTOH, when you're snowploughing like that you've got no steering, and you'll have to climb out over the plough wedges to get moving again!

Edited 6 December, 201015 yr by KenONeill

Would doing this help?

Surely in a modern car you cant come to a stop by just using the clutch as the anti stall kicks in! well at least mine does!!...but i still brake by using the gears

K:)

Surely in a modern car you cant come to a stop by just using the clutch as the anti stall kicks in! well at least mine does!!...but i still brake by using the gears

K:)

True, but if you've got it down under about 10mph the ABS won't work anyway.

Surely in a modern car you cant come to a stop by just using the clutch as the anti stall kicks in! well at least mine does!!...but i still brake by using the gears

K:)

That's not anti stall that a diesel engine

That's not anti stall that a diesel engine

Technically it's idle stabilisation control, but it does the same job as anti-stall if you try and "slow stall" the engine.

It did it my petrol 1.6 ford focus that i had and the service guys called it an anti-stall!!..a mate had a peugot that had the same function!!

But even if i have the car at snails pace (below 10 mph) and release the clutch the car will gain speed then settle into a constant speed.

K:)

Winter tyres!

Pull the fuse for ABS?

Kev

Didn't the original quattro have a switch to turn off the abs for such circumstances?

But for slippy conditions my approach is just to use the engine. Given the power of modern brakes and the large front bias its incredibly hard to to get fine balance right. And abs just isn't clever enough yet.

Brakes or gearbox, down hill on ice you have no chance until you find a good surface.....

To the OP :no:

The brakes on a car consist of a metal disc with some friction material pressed against it to transfer energy from the disc to the pads. Eventually the components wear out through the friction.

The clutch in a car consists of a metal disc with friction material pressed against it ....

What's going to happen to the clutch if it's used as a brake?

Im pretty sure the clutch can be used as an additional aid to car control (beyond just disengaging/engaging drive). I must admit your right in that it will wear out, but when safety is the issue id use any option i had to keep some control!!

J

From a "what is best for the car" point of view, then using the clutch to brake with isn't a great thing - but on the other hand using the clutch rarely for a situation like that when you are controlling the car through snow is much better for control. This is purely down to the downside of friction against traction.

Firstly we need the understanding that the closer the speed of the wheels are in relation to the road surface directly affects how much control you have. Wheels stopped and road still moving past (skidding) being the worst end of the scale, wheels moving at the same speed as the road equals full control. Apologies but the rest makes no sense if i assume everyone gets that

Lets look at braking first. You need to visualise how much friction is required to keep the wheels turning but with the brakes applied (as we are aiming to brake whilst still keeping the wheels from stopping to keep the control high). As we loose traction between the wheels and the road the amount that you can apply the brakes becomes much less, and the important thing is that when that traction is lost, the friction of the brakes takes over locking everything - at this point, the brakes are either on fully (skidding) or off fully. With the brakes on, you loose steering control, but gain (a small amount of braking) - with the brakes off you regain steering control but have no braking. Neither of these situations are ideal.

Now looking at using the clutch, we have the same friction v traction issues here but with one important fact, we can control the amount of stopping force we apply with much much more precision. When the friction overcomes the amount of traction we have, the wheels no longer lock up - instead they start turning at the speed of the engine. leaving you with the best of both worlds, some stopping force and some steering control.

Being in the correct gear for your speed whilst on snow is near one of the most important parts, but regardless of what braking technique you use if you end up on an steep icy hill and loose traction - pucker up, don't plant your foot on the brakes (release them if you need to change direction), ensure your gearing is as close to your intended speed as possible, hope you steering skills are up to scratch and that god is on your side

Simon, are you actually saying that you can change the amount of torque the engine applies to the wheels by single lbtf, and that braking 2 wheels is better than braking all 4?

Didn't the original quattro have a switch to turn off the abs for such circumstances?

The best way is to use a 4x4 Yeti

Some of the 4x4 Yeti have an offroad button and that alters many engine settings, including restricting the revs to 2500rpm max. it also changes the ABS and allows it to lock the wheels and provide a wedge. (standard on 4x4 Elegance models, option on SE)

Oh, and couple that with winter tyres. a winning combination.

I was blown away by the stopping ability of that combination up in Scotland before Christmas on the ice and snow.