On Thu, 20 Jul 2017 01:45:17 -0000 (UTC), Mad Roger
wrote:

On Wed, 19 Jul 2017 18:06:55 -0400,
wrote:

It CAN be true though at certain speeds, with certain engines, because
you drop the RPM of the engine, and if that drop gets the engine "off
the cam" the torque output of the engine suffers , in some cases a
WHOLE LOT.

It seems that the torque curve is almost everything when it comes to adding
inches to the diameter of the tire and wheel assembly.

Without knowing the torque curve, there's no way to predict the result, but
most accounts I referenced said that your chances are greater that you'll
lose mileage than you'll gain it.

But, everything depends on the variables, which I tried to remove in the
original question - but - they return with a vengeance because the
variables determine whether or not you gain mileage - not the diameter of
the end result.
You need to know that vehicles were often available with several
different optional gear ratios. If it had a hign numeric rear end,
like a 4.11 , you could gain milage with bigger tires - get the same
mileage as sat 3.55 gears - or mabee 3.23. Buying 3.23 gears and then
putting big tires on it generally would hurt mileage

On my Ranger, with 3.55 gears from rhe factory and they come as high
as a 3.08 and as low as a 4.56. The bigger wheel is still not as high
(effectively) as a 3.08 with the small wheels (would require a 15%
oversize) I upsized 9% - so 3.25 woth the snows - a little less on the
summer tires - 3.31 equivalent