Changing tire size Motorhome

[Brian Sexton]

Hello Everyone,
I am currently in the process of changing my drive tires on the motorhome.  My original tires where Goodyear 265/75R22.5, when I switched to Michelin's the size is now 255/80R22.5.  I plan on leaving the Michelin's on the front as they are only 2 years old, but would like to upgrade my rear tires to improve my load caring capacity which is right at the limit due to my generator in the rear of the coach next to the engine.  I would like to move up to 275/70R22.5 tires which would accomplish this.  I have research size comparisons on the internet and the results are below.  Seems the only real difference would be the difference in tire width of .4 in and wonder if that or anything else should be of a concern.  Thanks

Size           255/80/R22.5     265/75R22.5   275/70/22.5
Diameter        38.6                     38.1            37.7
Width       10                     10.4       10.8
Sidewall        8                               7.8         7.6
Circum      121.1                     119.8       118.2
Revs/Mile      523                      529        536
Load Range    G                               G                  H
Load       5205                     5205           6925

[Gerald Farris]

Brian,
It looks like the tire size change will work for you if you have enough offset with your rear wheels. The rear wheel spacing can be critical when considering going to a wider tire. You need to measure the distance at the closest location between your rear tire sidewalls when loaded, and make sure that you will still have the minimum distance that is published in the tire spec sheet with your new tires. If you do not, you can get what is called tire kissing, and that will cause a blowout.   

Gerald

[Brian Sexton]

Thanks Gerald.  Has anyone else with a circa 2000 Beaver Contessa or Patriot upgraded to 275/70R22.5 tires?  Any problems??

[Carl Boger]

My 1998 Patriot came from the factory with 275/70R/22.5 tires, and is what is listed on the placard by the drivers seat.  I recently put on Continental HSR2SA on in that size and really like them so far even though I only have about 60 miles on them.    These give me a J load rating and ride much better than my old wore out mismatched set.

[Brian Sexton]

Would there be any issue with having 275/70R22.5 on drives and 255/80R22.5 on my steers?

[Al Anderson]

The only thing you could run into IF you have ABS would be a fault with it reading different speeds at different axles.  With the minor size difference you are talking about I would doubt that would ever become a problem.

[Brian Sexton]

One concern I have is that I have 22.5 X 7.50 Accuride rims, is anyone running 275/75's on these rims?  Any issues?