robert nanzig wrote:
scary story snipped...
>     Now the questions.  Has this ever happened to anyone? What material
> is the knockoff made of-softer than the hub? Could the fact that I did
> not lubricate the threads after completely cleaning them this spring
> have contrbuted to excessive wear-or my participation in the autocross
> at SUNI?  What about the other 3 wheels? What would you do?
> 
> Rob Nanzig
> 67SV              Bolt ons are looking pretty good right about now!
Rob,  First of all, glad to hear that you were not hurt.
Yes, the knockoff is made of a softer and less strong material, mine looks 
to be chrome plated brass.  The hub is a steel piece.  I have never heard 
of the threads shearing. maybe someone else has.  Although I can imagine 
shock loads causing the thread to shear, it is hard to see hard cornering 
forces being sufficient to do this.
Are the wire wheels original - allowing full thread engagement?  My 
knockoffs have about 3/4 inch thread engagement.
Lubricating the threads provides two benefits: reducing potential corrosion 
and allowing proper torquing of the knockoffs.  Without the lubrication one 
is more likely to think that the knockoff is fully tight before it has been 
adequately tightened.  If this where the case and the wheel was loose on 
the hub, then this may have caused or contributed to the thread failure.
One other thought, if the threads had been buggered up in the past (such as 
having been cross threaded) then there may have not been sufficient thread 
strength to retain the knockoff.
In any case a carefull examination of the remaining wheels is in order.  If 
it where me I would look for: the thread shape on the hub, the thread shape 
on the knockoff, ensure that the knockoff has sufficient thread engagement 
and that the knockoffs are tight.
Thanks for the heads up and glad to hear that you escaped injury.
-Roger
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