There seems to be a recurring question of whether or not you can change the brand or size or load range of tires on an RV. There are a few individuals who have interpreted the Federal Regulations on tires that apply to the vehicle manufacturer and they want to apply the same regulations to the current owner of the RV.
Since I had to live under Federal Regulations for almost four decades, as I developed and tested many different types and sizes of tires, I do not agree with the idea that owners are prohibited from making changes—with one basic exception. The load capacity of the new tires must be equal to or greater than the load capacity of the original tires.
I have seen a question like this one: “My research (curiosity vs. need) is that LT and ST tires are not sold in the same sizes, so changing RIMS would be required?”
Here is my reply
The key items to confirm
- Is the load capacity of the new tire equal to or greater than the original tire when you consider your new intended cold tire inflation? This does not mean +/- 25#. It means “equal or greater.”
- Is the speed rating equal to or better than the original tire when you consider your intended new cold inflation level? (Yes, some tire load capacities are a function of speed.)
- Are your wheels rated for the inflation level you intend to run with your new tires? This limit may not be easy to learn, but wheels can fail from too high a pressure just as they can fail from too many pounds load. The pressure we are talking about here is always the COLD inflation pressure.
Have a tire question? Ask Roger on his new RV Tires Forum here. It’s hosted by RVtravel.com and moderated by Roger. He’ll be happy to help you.
Read more from Roger Marble on his blog at RVtiresafety.net or on RVtravel.com.
##RVT1086
After the 16 inch cheap crappy tires on my 5er went away I put the same tires on that my truck ran. Firestone 500s at 50 psi only.
I trust that is a joke post as the 500 hasn’t been made in decades and certainly not rated for 50 psi. Should the post be removed Gary?
I increased the tire size on my Forest River TT. I bumped them up 1 size and gained aboout 200# capacity on each of the 4 tires. Now, that does not mean I will load the trailer any heavier than it is rated for on its door sticker….but it gives me peace of mind knowing I have a bit more safety margin. And yes, the rim width was still in the the proper range for the larger tire.
Good idea
Are tires in tandem like most rv’s considered dual for rating purposes or do they have to be side by side to be a dual arrangement? You see single and dual rating on tires.
Tandem (1 in front of the other) is not considered the same as Dual (side by side on end of an axle)
HERE is a post showing the difference.
Another fact based data driven article from Roger as allways. No bias or opinions.
Yep 👍
Thank you, Roger! This is a very helpful discussion, especially in light of the long lead times required to get some tires. I i tend to opt to run the same tires (manufacturer and size) when mine age-out. But, that intent may change based on the circumstances when it is almost time to replace. Thanks again, and safe travels! 🙂
My Chevrolet crew cab dually recommends D rated tires. I run E rated at 75 PSI and haven’t had any issues. And I haven’t been pulled over by the tire police.
Seems OK to me.
No the “Tire Police” are not going to stop you.
Roger, your opinion please….Class A MH, Michelins beginning to age out. Would it be ok to change out the front tires to Toyo (same size/capacity as Michelins) this year, then the rear duals to Toyo next year? Is it ok to mix brands?
I would have no problem with mixing brands as long as you stay with same size and capacity. BUT do not mix tires on the same axle, especially in dual tire applications. Duals need to be matched in physical size unless you are applying new tires. See my blog post at http://www.rvtiresafety.net on matching duals.