safe to change tire size?

[ToddDianeL]

Recently purchased a 38' Dutch star and it needs new tires.
It currently has the 255/80r22.5's across the rear and 275/70r22.5's on the steers.
The only tires available in 255/80's are the Michillens which are quite expensive in comparison to the other sizes.

I am considering installing 265/75's all around and my concern is that these tires are 4/10's of an inch wider than the 255's which will decrease the gap between the duals by that much. There is roughly 3" space between the 255's that are on the coach right now.

Has anyone done something similar with their tire sizes and what were the results?

Thanks in advance.

[ToddDianeL]

Thanks to everyone who has responded and provided information regarding this.
I have measured the dual spacing and it is right at 12" as it sits now.
The rim size on the placard is 225x7.5

I am going to look into the 265/75's some more and make sure that I am confident with the information and feedback I acquire as I move forward.

[hooligan]

Bob--It's easy:
Tire Calculator

[BobandShaz]

Not sure how but I would really check the change out

[hooligan]

Todd: Dual spacing should not be a problem. Minimum spacing for the 255/70 is 11.3 inch, for the 265/75 it is 11.6 inches. Spacing is a function of the wheel offset and can be measured from the center of the tread of one tire to the center of it's paired dual.


HDS is Half Dual Spacing and is the rim offset. My Accuride 22.5 inch wheels have an offset of 6.44inches each so dual spacing is 12.88 inches...

[Francesca_Knowl]

wolfe10 wrote:

Francesca Knowles wrote:
Here's the straight skinny from another thread on the same question:

Hooligan wrote:
Posted By: hooligan on 05/28/10 06:04pm

Mike: The 235/80R22.5 is a Michelin size. The equivalent by other mfgr is 245/75R22.5, same specs, diameter and loading. Load Range G

255/80 CAN be replaced with 265/75R22.5 in most every case. Just verify rim width, dual spacing and suspension/body clearance.

235/80R22.5 is a completely different size/issue.

DANG!
I captured the wrong quote. This is the one I should have posted: will fix above, too.

hooligan wrote:

These tire sizes by other manufacturers are direct replacements for the Michelin specific sizes.
Popular RV tire size equivalents:
.. Michelin..to...Goodyear, Toyo etc
235/80R22.5 = 245/75R22.5
255/80R22.5 = 265/75R22.5
275/80R22.5 = 295/75R22.5

[wolfe10]

Francesca Knowles wrote:
Here's the straight skinny from another thread on the same question:

Hooligan wrote:
Posted By: hooligan on 05/28/10 06:04pm

Mike: The 235/80R22.5 is a Michelin size. The equivalent by other mfgr is 245/75R22.5, same specs, diameter and loading. Load Range G

255/80 CAN be replaced with 265/75R22.5 in most every case. Just verify rim width, dual spacing and suspension/body clearance.

235/80R22.5 is a completely different size/issue.

[sailor_lou]

Although it sounds like you will still have sufficient space between the rear duals, I would consult the tire manufacturer. I'm not all that confident in the knowledge level of most tire shops.

One additional point to consider is clearance when the air bags are deflated. I know on my rig when the suspension is dropped I have about 1/16" between the rear tires and the fiberglass fender. If the tire was any wider I'm sure the fender would get damaged when the air bags dump. Good luck.

Lou
05 Travel Supreme Envoy

[Francesca_Knowl]

Here's the straight skinny from another thread on the same question:


ON EDIT FIX:

hooligan wrote:

These tire sizes by other manufacturers are direct replacements for the Michelin specific sizes.
Popular RV tire size equivalents:
.. Michelin..to...Goodyear, Toyo etc
235/80R22.5 = 245/75R22.5
255/80R22.5 = 265/75R22.5
275/80R22.5 = 295/75R22.5

[Fleet_Man]

I did exactly that last June. The 265/75's are the closest in overall diameter to the 255/80 thus virtually no effect on the speedometer or odometer. If you have 8.25x22.5 wheels, you have no concern with the increased width of the new size, a 7.5x22.5 wheel might create some concern and would have to be checked out for sufficient clearance. I went with Bridgestone R250's and have zero complaints in any department.