[s-cars] More on audi wheel bolts/studs/torque

Robert Pastore rpastore at animalfeeds.com
Tue Oct 22 08:55:36 EDT 2002


I wasn't suggesting that backoff torque meant anything, only sharing the
mistake I made:

With a "clicker" style torque wrench, checking torque when the lugs were
very hot by adding torque until the wrench "clicked" appears to have added
torque on each successive "test"; then at the end of the day when the lugs
were cold and I tried to remove the nuts, I had some real problems.


-----Original Message-----
From: Bernie Benz [mailto:b.m.benz at prodigy.net]
Sent: Monday, October 21, 2002 10:55 PM
To: Robert Pastore
Cc: 200q20V mailing list
Subject: Re: [s-cars] More on audi wheel bolts/studs/torque

The thermal considerations are of small importance. but higher temps will
slightly increase the clamping forces, because of the larger coeff of therm
exp of alum vs steel, which in turn will increase the creap deflections
within the aluminum, and thus reduce the cold dynamic clamping force. All
this assuming that we can ignore bolt friction changes caused by temp
changes in a poorly lubed bolt.

Backout torque is of no concenquence, unless you wish to remove the bolt.
Then you wish that it had been properly lubed.


> From: Robert Pastore <rpastore at animalfeeds.com>

> I guess I just added torque with each round of "clicks" when the stuff was
> very hot.   Then when it cooled, I was stuck.  Now I back off in reverse,
> then tighten to the spec.
> Bob

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