> This might help explain part of the argument about positive and
> negative. Compomotive says:
>
> http://www.usacomp.com/Offset.htm
Great. No wonder we can't agree on the definition, even the wheel
manufacturers can't get it straight!
However, I believe the term "wheel offset" is defined by both SAE (Society
of Automotive Engineers) and DIN (Deutsches Institut fur Normung); and they
say Compomotive has it backwards. Unfortunately I don't have a reference
handy, does anyone else ? It's supposedly in the SAE handbook, but I only
have the Bosch one (which shows it in a diagram but doesn't specify which
direction is positive).
I did find a rather long winded thread that suggests the definition of
offset has been changed :
http://realbig.com/detomaso/1998-02/1319.html
Interesting to note that Compomotive apparently also measures rim width
between outside edges, instead of between bead seats. Now I _know_ there's
a SAE standard for that, and it says it must be measured between the bead
seats and marked on the rim (which is why TR6 rims bear the legend 5.5J even
though they are roughly 6" lip to lip) ...
Randall
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