Snow Chains

In article , Ian Spare
wrote:
On Thu, 18 Dec 2003 12:37:14 +0000, Mike Clark wrote:


The Subaru system is a permanent AWD, with on some vehicles such as my
Forester a high and low range gearbox. It is not a locking differential

Having a high/low box is really useful, I miss this on my Quattro. In
all ways the Quattro handles way better on snow and ice than the
Cherokees I used to have did. Descents are much better with the low
box though.

I'd guessed the Forester had one, I'd also guess the Audi Allrad and
the volvo XC also have them.


The Subaru non-turbo models have the high and low range gearbox, the
turbo versions have a single ratio.


Mike Clark, URL:http://www.path.cam.ac.uk/~mrc7/
--
o/ \\ // |\ ,_ o Mike Clark
\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
" || _`\,_ |__\ \ | immunology lecturer, antibody engineer and
` || (_)/ (_) | \corn computer user"

On Thu, 18 Dec 2003 14:37:02 +0000, Mike Clark wrote:

In article , Ian Spare
wrote:
On Thu, 18 Dec 2003 12:37:14 +0000, Mike Clark wrote:


The Subaru system is a permanent AWD, with on some vehicles such as my
Forester a high and low range gearbox. It is not a locking differential

I'd guessed the Forester had one, I'd also guess the Audi Allrad and
the volvo XC also have them.


The Subaru non-turbo models have the high and low range gearbox, the
turbo versions have a single ratio.

The Volvo V70XC/XC70 is also a single ratio. I guess it's possible
that the XC90 has hi/lo, but I don't recall seeing it when looking at
one in the showroom.

--
Ace (brucedotrogers a.t rochedotcom)
Ski Club of Great Britain - http://www.skiclub.co.uk
All opinions expressed are personal and in no way represent those of the Ski Club.

VW/Audi recommend all quattro's are fitted with chains to the front wheels
only. They actually provide a warning not to put chains on all four wheels.
With Quattro/4motion it is irrelevant where the power is sent under normal
conditions (it happens to be biased towards the front on all models because
for 'safe' understeer handling) because the system will send power to
wherever traction is available

The TT/A3/Golf FWD versions use a Haldex clutch (not a diff) which only
sends power to the rear wheels if the front loses traction. It may try to
send power if the front lose traction but the brakes will be applied to
prevent any spin at the back whilst de-powering the engine. The same system
I believe is used on the Freelander but I may be wrong.

The other quattro models (A4/A6/Allroad/A8/Passat) use a Torsen diff which
provides power to all four wheels permanently. However if traction is lost
to any wheel it will redirect the power to the other three wheels. So it's
logical to put the chains on the front for better steering and improved
braking performance. The rear wheels will be braked if they start to spin
diverting the power to the front. Again the engine will be de-powering if
the fronts start to lose traction.

Richard Lawson



"Ian Spare" wrote in message
...
On Wed, 17 Dec 2003 19:47:00 -0000, "Michael MacClancy"
wrote:


"test" wrote in message
...
John,

Same story on my VW Passat which has made a few trip down to France and
Italy, think I've used the chains on three occasions, once for the
entire
10
days in Courchevel with no probs. Think it is VW covering their backs
re
clearances etc. Now the TT handbook has the same statement but not sure
quattro can cope with chains at the front but not the back..

My understanding is that 4WD vehicles should have chains on all 4 wheels.

No, that's wrong. For a start not all 4WD is equal, and more to the
point not all 4WD drive front and back axles equally. For normal
conditions chains go to the rear wheels which will be receiving most
of the drive. You'd only really chain all wheels for serious offroad
work.

The earlier comment about the TT is intriguing. my A6 quatro would
have chains at the rear wheels, I've not driven a TT quatro, is it
sending more power to the front wheels than the rear I wonder ?

Ian

Here is a handy three-point fool-proof guide to fitting chains to
vehicles with two wheel drive, front wheel drive, all wheel drive, six
wheel drive, etc.

1) Use the manufacturer's recommendation

2) Use the manufacturer's recommendation

3) Use the manufacturer's recommendation


Why ? Because if your smart enough to know that you don't need to use
the manufacturer's recommendation, your smart enough not to have to
ask....

On Thu, 25 Dec 2003 17:05:17 +0000, funkraum
wrote:

Here is a handy three-point fool-proof guide to fitting chains to
vehicles with two wheel drive, front wheel drive, all wheel drive, six
wheel drive, etc.

1) Use the manufacturer's recommendation

2) Use the manufacturer's recommendation

3) Use the manufacturer's recommendation


Why ? Because if your smart enough to know that you don't need to use
the manufacturer's recommendation, your smart enough not to have to
ask....

Aprt from the fact that the manufacturers recommendation for chains
tends to be to suggest that there's something exotic and unusual about
your car and the only possible way to proceed is to pop down their
parts shop and part with 5 times the going price for some indifferent
chains. (Repeat for roof bars, roof boxes and winter tyres)

They'll probably have it right which wheels to put them on though.