In a message dated 1/31/01 3:03:38 PM Eastern Standard Time,
drillock@EARTHLINK.NET writes:

<< At least at low speeds there is no meaningful
 difference. I just did the "mustard" test on both left side wheels, and
 then let most of the air out of one tire and did the mustard test again.
 The facts speak for themselves. >>

 As a long time bus and van owner and a transmission rebuilder I have to
comment

WHO CARES?..I mean really, there are only a few combinations of tire sizes,
ring and pinion and gear ratios available..It's a big box with a little
engine.. SO..for most application the STOCK tire size and gear ratios are
FINE. Granted, if you do nothing but interstate cruising in the mid west and
are empty all the time, slowing the engine relative to the road speed might
pick up one or two MPG (until you hit a head wind)
Conversely, hauling depleted uranium up a goat trail to Machu Pichu is going
to require a bit lower ratio than you might have gotten stock...
You also might want to do a cost comparison.It seems that you (on paper) are
will to spend LARGE amounts of $$ to pick up (or not!) some SMALL advantage.
I converted a few 1972-74 bus gear boxes to work with Vanagon diesels..ones
that were NEVER going to be required to start on a hill at maximum gross
weight...and it's about right for most people (53 vs. 42 in 3rd gear) Sooooo
Don't loose much sleep over tire sizes. I'd be more worried about clearance,
and offset and load rating than diameter..I run the reinforced continentals
or Michelins..they just seem "right".
I will not go into brake efficiency or biasing when you start switching tires.
185-14's or the 205 14's were picked by people who knew what they were
about..yes, they are compromises.. Drive on soft ground a lot? go to the
205's (215's?)
You will find the different brands of tires are different diameters
As far as the growth...I've got 71 lb/ft of torque, 4000+lbs of dead weight
and a CD up around .46....SOMEHOW I can't see where worrying about the
"overdrive" effect of the tires growing with speed will cause me to have
custom gears made to "correct" my 0.77 5th.....
It's nice to know, but don't lay awake staring at the ceiling over it

steve...

"Hey! nice Jeep, Mister!"
"Look kid, it's NOTAJEEP"