Philip J Ethier tells us that TR7 wheels, like the
>Spitfire, GT-6, TR7, TR8, Elan
use a 3.75" bolt circle. But there is more to it than that.
I bought new wheels for my TR7 based on the advice of my
mechanic, who said:
"There is a design problem with the way those stamped wheels
are attached to the hub with the shape of the nut -- they
eventually self-destruct. You should buy new wheels."
I bought new wheels with the right bolt center. They never
ran true, but TR7s are notorious for not running true, so I
thought that I would have them balanced "on-the-car" when I
bought new tires. When that happened, I found out that the
front wheels must be "hubcentric," in other words, the locating
device for the front wheels is the thing that sticks out in
the middle. The hole in my wheels was 0.034 inches too large
in diameter for the hub, so it was located by the studs and
nuts, which are not located accurately for a true wheel. Thus,
the car resonates at 55 m.p.h. (I have been able to shim the
wheels so that they now locate correctly.)
The rear wheels, though, are not hubcentric -- they locate by
the studs. Weird, huh?
--Joe Gorin joeg@sr.hp.com '80 TR7 Convertible owner
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