PT 40, 42 & 43 owners. A ? about your tire size

[Kurt Horvath]

After a 2 hour web search I can not find anybody that makes a tire in
315 75R 22.5.
Everybody has a 315 80R 22.5 they are about 1" wider than a 12R 22.5
& 11.3" Vs 12.5" in width, and the 315's are a little shorter,19.6"
Vs 19.8" loaded radius, overall diameter is the same @ 42.4", they
both use 9" rims, the 315's have a 1700lbs single wheel higher
capacity and a 1465lbs higher dual wheel capacity, per tire.
The only thing I see as a problem may be the dual wheel spacing.
13.2" for the 12R and 14.1" for the 315's. The only other difference
is revolutions per mile, I'd say insignificant @ 2 RP Mile. Info from
B.F.Goodrich. The only chart I could find without bouncing all over
the web
I've seen several size tires on comparable birds PT 40,42,& 43's,
I've seen coaches with 11R 22.5, and the coach for sale on e-bay
states it has 315's on it..
Convention wisdom states all tires should be of the same size & Mfg.
I would like to have the heavier tires on the steer axles. I don't
think 1/2 inch wider on each side of the tire in the front wheel
wells would make a difference, though it is already a tight fit., and
I'm not sure if the larger tires would have an adverse effect on the
overall drive ability. I'm hoping for better control , higher
capacity and the added safety in a more capable tire.
Any thoughts?

Kurt Horvath
95 PT-42
10AC