RV Tire Safety
with RV tire expert Roger Marble
I continue to read RV forum posts from people asking about what inflation to use. Tire sidewall, sticker, owner’s manual? The inflation used by a neighbor? There is also continued confusion on what the sticker inflation is.
The “vehicle certification label” aka the “tire placard” only considers one thing: the maximum tire load capacity (molded on the tire sidewall) when the tire is inflated to the level associated with the original tire load range (ply rating) as shown in the industry load and inflation tables.
Federal DOT regulations specify that the label indicate the tire inflation level needed to support at least 50% of the GAWR (gross axle weight rating). NOTE: There is no margin or reserve load capacity specified or required by the DOT regulations.
Starting in November 2017, the RVIA (RV Industry Association) required that trailers have a 10% margin on tire load capacity. Motorhomes do not have this margin requirement from RVIA as far as I know.
Tire companies do not know the exact loading that will be placed on their tires in an RV application, so you have to do a little work to learn the minimum inflation needs for your personal vehicle. You could simply use the inflation on the tire placard, but you still need to confirm, with scale measurement, that no axle is loaded more than the stated GAWR.
It is also strongly recommended that you confirm your side-to-side load split is close to 50/50 as the tires do not “know” what the other tires are supporting, so you could be unknowingly overloading one tire by hundreds or even 1,000 pounds.
I have other posts in my blog on how to learn the individual tire loads.
Read more from Roger Marble on his blog at RVtiresafety.net.