RE: [T3] wheels

["Jaranson, John (J.W.)" <jjaranso@ford.com>]

Actually, "backspacing" and "offset" are two different dimensions on a
wheel.  They are often used interchangeable in conversation, but are unique.
It is also important to know the difference and to check with your wheel
supplier when ordering to find out which measurement they are using.

Backspacing is the distance measured from the mounting surface of the wheel
to the inside rim edge.  Backspacing will always be a positive number,
unless you have a VERY strange wheel.

Offset is the distance measured from the mounting surface of the wheel to
the centerline of the wheel.  Offset can be either positive or negative.
Deep dish wheels will have a negative offset.  Most production wheels have
positive offset including the T3 wheel which is either 43mm or 46mm.   I
don't remember which.

As an example, a 6" wide wheel with a 2" offset would have a 5" backspacing.
Alternatively, a 6" wide wheel with a negative 2" offset would only have a
1" backspacing.

This would be a great place for a picture, but..........no attachments. 8^)
Instead, check out the TireRacks website.  They have a good picture in their
Tech section.   http://www.tirerack.com/wheels/wheels.htm  They don't call
out the backspacing specifically, but it is:

Backspacing = Offset + Half of the Width

Later,
John Jaranson
'71 FI Auto Fasty
http://hometown.aol.com/jaransonT3


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