differential windup and damage

[Peter Golledge]

Gents,

Another way to look for data how many manual Audis do you see at wrecking
yards with shot transmissions?  My count over the years is 0 and some of
these cars don't even having matching tyre _sizes_. :-)  I run the LT-1Q as
mostly a track car, I'm cheap so quite often there is significant wear
differences between left/right.  This car has done some 40K hard road miles,
multiple Gruppe-Q (http://www.gruppe-q.com) events runs 400ft/lb of torque
and the stock gearbox/diffs are still fine.

Now tyre dealers/companies are always going to say: "You have to have
perfectly matched tyres" since it sells more tyres. 

-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] On
Behalf Of Huw Powell
Sent: Wednesday, October 11, 2006 9:53 PM
To: Bluemaxww1 at aol.com
Cc: quattro at audifans.com
Subject: Re: differential windup and damage


> The theory is this, and proven on Semi trucks and other large trucks 
> such a Dumps, Haulers, etc.,  different diameter tires, such as one worn
and one  new
> tire of the same size, cause the axles to rotate at different speeds.
This 
> puts undo pressure on both sides of the diff.  This will  eventually 
> cause the diff to fail.  Not urban legend.  The same will  happen in a
car.

How long would you need to drive in a circle (or oval...) to do any harm?

> The report on the trucks was in a maintanence magazine for fleet
companies.  
> Our Utility followed the advice, and the diff failure rate went  down 52%.

> Savings in the first year of replacing pairs, or in some cases,  quad 
> tires, was close to 1M.  The rear tires not worn out enough were  
> simply used on the fronts as replacements.

There must be documentation of this somewhere.  That's usually the
difference between urban legend/rural folklore/"street knowledge" and facts.
I realize it might not be on the www, but surely there is something
authoritative.  $1M a year savings usually come with some paperwork, I'd
imagine.

So far, all that I can assert is still that "I heard it somewhere".

--
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/
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