On 6/2/2011 3:19 AM, Paul Hunt wrote:
> 60ft lb. 75 ft lb should be avoided but shouldn't do any damage on
> an MGB, but could on cars with a smaller diameter stud like the
> Midget. A while ago I had two tyres replaced somewhere I hadn't
> used before. Unlike other places I have used owners are forced to
> spectate from a separate enclosed area through a window for 'elfin
> safety'. It looked to me like he used an air gun to do the nuts up
> until it chattered, and only used the torque-wrench to check that
> they weren't under-tightened (instead of spinning the nuts on with
> the gun or brace and then using the torque-wrench for the actual
> final tightening). On return home I started checking how much force
> was needed to undo them with my torsion-bar torque-wrench. The
> first needed 100ftlb, the second got up to 120 then the torsion bar
> snapped, I had to undo the rest with a breaker bar. After that most
> of the nuts felt wobbly on the threads (loose on the stud, not
> clamping the wheel), whereas the rears didn't. Swapping fronts to
> rears the rear nuts on the front studs felt OK, but the front nuts
> on the rear studs were still wobbly, so I replaced all the nuts (V8
> so not cheap) as a precaution. Of course, a complaint to the
> fitting company got nowhere, even involving Trading Standards.
>
> Having said all that I never have used a torque wrench when
> refitting wheels, but simply lean down hard on the standard tool,
> stamping down on it always loosens them. After the above and out of
> interest I did try tightening to 60 with my (new!) torque wrench and
> loosening as I usually do, and vice-versa, and found it came out at
> about 60-65 ftlb. If you use one of those girly expanding wrenches
> you should tighten the nuts with it closed, or use the vehicle
> manufacturers tool, and only use the expanded wrench or breaker bar
> for undoing.
It took me a couple of days to find out who to complain to about a similar
matter, where a tire company torqued the wheel nuts on a friend's Honda so
tight they would not unfasten. That's actually a potentially life-threatening
error. I want a State Law that forbids using an impact wrench to tighten wheel
nuts.
-Rocky Frisco
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