Driving in snowy/icy conditions (and electronic driver aids)

[Konan555]

In theory, the front wheels only need to turn about 1/7 of a sinlge rotation to begin transfering torque to the rear diff.

I'm sure I've seen a lot more slip than that on a Haldex when launched hard.

[badass]

you know what?... Horrible thought... but I think you might have had a technical issue on that car.

In theory, the front wheels only need to turn about 1/7 of a sinlge rotation to begin transfering torque to the rear diff.

maybe you had a sensor out somewhere?

As both front wheels have an ABS sensor, in theory the torque should be moved to the rwar while putting the brake on the slipping wheel and it should occur very very fast... definately in split seconds... un countable time. I'm sure the pump for the oil pressure is suposed to be pre loaded.. so it can kick in dead fast.

I honestly didn't think that BOTH front needed to be slipping for the HALDEX oil pressure to move torque to the rear.

What dya think? Might have been unwell?

You know what - I didn't think of that and I haven't driven another A3 quattro to compare.
I'm going to change my position on "fake" 4WD from "crap" to "reserve judgement" until I've driven a known good one.

That car had clearly been abused in its former life, hence why I am rid of it. I miss the V6 though
My current A3 may get me 8-10 MPG more on the same drives but the V6 took off like a scalded cat, had a lot more pull over 3500 RPM and sounded much nicer.

On the even tyre wear, any smart garage will rotate the tyres on an A3 quattro every service as they all need to have even wear for the 4WD to work properly. Maybe thats why all 4 tyres seem to wear evenly?

[Phage]

Certainly not my experience. See my post number 27.

[1stRaven]

I

• managed 2nd set of wheels for £120.
  
• Winter tyres I opted for where a little cheaper than what I usually run per corner.
  
• They took 1mm total tread depth off last year in the 3 months I had them on. This is around the same as I observe from my regular tyres.

So it's £120 for me, which I feel is a sound decision made by someone in their right mind!

If I could get anywhere near the £200 mark, then I agree, it is a sound decision but there is only a choice of 1 or 2 tyres at the size I need. Currently Camskill show 1 option (which is out of stock) for the rears at £283.80 each and the fronts are £190.40 each (again, only 2 options with 1 out of stock). Tyres alone then are £950.

I did do a quick search on ebay and there are none available in the tyre sizes I need. I could drop down to a 17" wheel as there are some options for alloys/steels there but none second hand (everyone buys them for winter wheels) and the last pair of alloys I saw went for £500. Tyres are still over £650 at this size.

My plan has always been that if the snow/ice gets too bad, get a lift into work or walk (its about 7-8 miles). Otherwise, just be aware that the stopping distances have been increased and drive accordingly.

[Butcher]

If I could get anywhere near the £200 mark, then I agree, it is a sound decision but there is only a choice of 1 or 2 tyres at the size I need. Currently Camskill show 1 option (which is out of stock) for the rears at £283.80 each and the fronts are £190.40 each (again, only 2 options with 1 out of stock). Tyres alone then are £950.

Mytyres (and others) have been selling complete wheels with winters mounted for about £150-200 over the cost of tyres alone, your choice of steelies or alloys. They'll be new wheels to so less concern about buying something trashed off ebay. Will be difficult to get much now as winter tyre stocks are likely to be pretty much gone until next autumn.

I got a set of new 16" alloys with winters fitted for around £800 (which is not far off what a set of winter tyres alone would cost for my summer 18" wheels) and that was dealer prices!
In terms of cost over just running summers it's a couple of hundred quid once for the alloys then it makes little difference. While you're wearing the winters out the summers aren't getting wear, and with the smaller size on the winters they're, if anything, slightly cheaper to replace.

As for the rotated wheels masking tyre wear, it's possible but unlikely. If that were the case I'd see additional wear on the fronts before the first service which hasn't been the case. My tyres wear quite noticeably between services as I run fairly soft tyres (summers are currently Michelin PS3s and last about 25k).

[1stRaven]

I did look at those but the biggest one they did was 16" which don't go over the brakes (although they are recommended for the car).

Its a bit late for me this year but it is something I will continue to look into over the summer to see if I can spread the cost.

As for tyre wear, I would expect a set of winters to last me 1-2 years, looking at the reviews etc. My last set of Falken 452's fitted in May had to be replaced in December as they were fully worn out.

[Zak33]

I'm sure I've seen a lot more slip than that on a Haldex when launched hard.

from one wheel, for a split second yes.

but as soon as the brake caliper catches it, making the other front wheel spin it SHOULD kick in to the rear.

But it's NOT torsen... it has no where near the brutal ability of torsen. It DOES however work well.. and kicks 2wd to death in snow.

but the complaints from drivers of 4wd cars of other era's/types come thick and fast...

I saw a bloke doing a rapid start holding it on the handbrake once......and another left foot braking and complaining of scrabble on a part time rally stage for people to whazz their cars about on.

unless you know which sensors turn off the haldex system you've got no chance of getting it to work.

[Konan555]

But it's NOT torsen... it has no where near the brutal ability of torsen.

From my experience with it (a little limited, not been in the latest gen), it doesn't have match the ability of a permanent viscous system either. Although that will vary, you can really feel a worn out centre viscous coupling 'lagging' when you spin an axel up.

[Konan555]

This clip amuses me....

http://www.youtube.com/watch?v=i-17TFNzw-0

I know there's all sorts of variables. The bit of grass they start on, driver, tyres. Having said that, it's exactly what I've seen an XC70 manage vs an Outback. Interesting the ranger appears slower. I guess that's old school 4x4 vs traction control AWD.