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Re: Torque for wheels nuts

To: Jean-Pierre Labuschagne <jpl@dbsa.org>
Subject: Re: Torque for wheels nuts
From: "Christopher M. Delling" <cdelling@mail.ic.net>
Date: Fri, 16 Aug 1996 09:24:31 -0400
Jean-Pierre Labuschagne wrote:
> 
> For what it is worth the original MGA workshop manual they say the
> following with regard to wheel nuts "Tighten the nuts to a torque wrench
> reading of 60 to 62,5 lb. ft (8,3 to 8,65 kg. m.). Do not overtighten."
> I do wonder would these settings change over the years due wear and tear on
> the bolts?
> And lastly the front end wheel clunk experienced on my MGA was due to the
> break shoes being incorrectly fitted and adjusted.
> 
> '57 MGA 1500
> Safety Fast


The fastener industry is highly misunderstood by many in our hobby.  
What is of concern in any bolted joint is clamp force.  Since there is 
no non-intrusive means to measure clamp force in the field, studies are 
done in the lab using special sensors to determine what clamp force is 
acheived with a given torque.  These are the numbers that we see in our 
manuals.  What is not addressed is whether this torque is acheived with 
a dry bolt, a dry lubricated bolt, or a wet lubricated bolt.  A 
lubricated bolt, tighted to "X" foot pounds will acheive a much higher 
clamp force that a dry bolt at the same torque - due to differences in 
the frictional coefficient between nut and fastener.  Does anyone have 
information on the type of lubrication (or lack thereof) was intended 
when the manuals were written?

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