Offset: + or -- ?

[BEast750F@domain.elided]

Godfrey,

I disremember which way is positive and which way is negative, and when it
occurs to me to ask, I seldom get an answer.  I gave up worrying about it,
though, because I never run into any car wheels that are offset in the
opposite way.  If someone is mentioning the subject, it is understood that the
bolting flange is closer to the outside than inside of the wheel.  

Regardless of plus or minus, that information is hard to use.  To measure the
offset requires finding the midpoint of the rim, which will be in midair, and
then the distance to the center flange -- 40 mm, for instance.  The way I do
it is to measure the rim width, say 6", divide that in half to get the
midpoint (3").  Then measure the backspace, say 5", subtract the 3" and you
have an offset of 2" [to the outside]. 

If I am out of line, throw cold water on me and bring me to my senses, but in
practical terms, it just seems easier to use the backspace info alone.

Bill

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