Re: Offset: + or -- ?

["David R Johnson" <johnsnd@domain.elided>]

On Mar 11,  9:34am, Godfrey DiGiorgi wrote:

> The Tire Rack page is what raised the question in the first place. Dave
> Partridge pointed out to me that the measurement described by Tire Rack is
> actually hub offset, not wheel offset ... it's a matter of point of
> reference. A negative hub offset produces a positive wheel offset. Thus my
> confusion.

Hmm, I have never heard anyone mention the term "hub offset".  Wheel offset and
backspacing are both commonly used.  A quick web search on the term "Wheel
offset" lead me to a variety of pages, all of which agreed with the TireRack
definition.  There was one exception, but that page contradicted its own
definition in the same paragraph, so its author was apparently as confused as
any of us!  One page provided a handy offset calculator, which tells you the
effect on the position within the wheelwell of substituting a new wheel of
given specifications (see http://www.mindspring.com/~toy4two/offset.html ).
 Assuming I correctly interpreted the results I got, this calculator also
supports the TireRack definitions.

I would speculate that the two terms "wheel offset" and "hub offset" became
confused in the distant past, and it is possible that by strict definition all
these sites are wrong.  However, if this is what is popularly understood by the
term "offset", particularly by large scale wheel selling outfits, then one has
to accept it even if it leaves a bad taste in the mouth (just as the
announcement "we will be deplaning momentarily" does at the end of a flight).
 It is clearly of critical importance to ensure that your definition agrees
with that of the person buying or selling your wheels.

Sorry if I have merely added to the confusion!

Dave J.
1982 GTV6

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