There is no single answer that is correct for all tires in all applications. The life experience of a tire on a car, light truck (LT), RV trailer, RV motorhome or commercial truck are all different, so each type of usage will get a different answer. A recent RV forum had a discussion trying to come up with a single age that was correct for every application. The answers ranged from 2 years to 10 years, so clearly there is some confusion.
Most passenger car tires usually wear out at 35,000 to 50,000 miles, in 3 to 5 years, so they get replaced when they wear out.
LT tires are similar, with 4 to 5 years life, unless used in commercial service when they get heavy loading and more miles each year that a passenger car tire.
Note: For both passenger and LT tires, a tread depth of 2/32″ or less is considered “worn out” in many states. Many find the “penny test” quick and simple.
When to inspect and replace tires
Michelin, Bridgestone and Goodyear—you know, the folks that know a little bit about tires—are on record as saying, in print, that tires should be inspected inside and out at about 5 years and each year thereafter. Also, they say tires in RV service should be replaced at 10 years “no matter what a visual inspection finds.”
Due to the special internal structural loading identified as “Interply-Shear” in trailer usage (pull-along and 5th wheel), I would suggest that you have tires dismounted and inspected at 3 to 4 years and replaced at 6 to 8, no matter what the visual inspection finds. Interply Shear is the force found in the rubber between the belts in the tread of radial tires.
The major reason for the different levels of Interply Shear is that tires in car service are only loaded to about 70% to 80% of their load capacity. Tires in RV service are loaded to 90% to 115% of capacity, based on load and inflation studies. Also the interply shear in a trailer can be 24% higher than in an identically loaded tire in a motor vehicle. This increased loading results in increased shear forces that work to tear the belts apart and off the body of the tire.
Roger Marble
Check out my Blog www.RVTireSafety.Net
Read more from Roger Marble on RVtravel.com.
##RVT1142
A very good reminder to know your tires age. Weigh the loaded RV and follow the tire manufacturer air pressure vs weight chart.
Just because it fits does not mean it’s safe.
True. Our spare always appeared to be in good shape until I checked the date on it. The tire was old enough to drive the RV itself.
I think I was part of that thread (although tire threads are everywhere!) I even recall posting something like “Hopefully Roger Marble will weigh in.” I know you frequent that forum with your always sound advise. Thank you!
When they say tires should be replaced at 6 years. Is that the start of the 6th year or at the end of the 6th year?
I have understood it to be at the end of six-years, when the tire is six-years old. If my tires are still in good condition, I do run my tires past the six-year mark. And six-years refers to the date of manufacture, so check the date code on the sidewall when replacing or buying tires. Buying a six-year-old, “new tire,” is still a six-year-old tire.
Thank you, Roger! The admonition to check tires inside and outside made me recall something I have heard or read (YouTube, iRV2, RV Travel, somewhere) recently that unmounting and mounting tires stresses them. If this is true, then I conclude that the risk of undetected inside wear outweighs the certain damaging (?) stress of unmounting and mounting a tire in order to thoroughly inspect it. True? Thank you! 🙂
When time to replace my trailer tires, I upgrade the load range if possible. Going from a load-range B tire to a load-range C tire if the rim is rated for 50-psi. The tires last longer and the trailer tows better because the tires are not as close to their maximum weight carrying capacity.