> But consider this:=A0 What if the inflation of the 4 tires is not equal, wh=
> ich is often the case?=A0 Wouldn't that affect the diameter by easily 1/2 t=
> o 3/4 of an inch?

Anthony:

Inflation does not affect the rolling circumference of the tire--how
could it, stretch the steel belts in the tread?  It does affect the
amount of tread in contact with the road; that's why Syncronuts
love to "air down."

Another option for you is to buy 2 new tires that are slightly
larger and have them shaved.  My tire shop here in Boulder does
a lot of that for Subaru folks who lose one tire when the others
are still good.

For Friday homework, you could think through the following:
The open diffs in our (stock) Syncros transfer power to the
wheel turning faster.  Hence to the "smaller" one.  So if
the "small" one on the rear and the "small" one on the front
are equal, the VC should be happy, regardless of the sizes
of the two "larger" ones, no?

Richard