Tire Inflation Guide

NC Hauler wrote:

past-MIdirector wrote:
Need to look at the load range on the replacement tires. Most RV replacement tires are one or two load ranges high with a higher max. pressure then what was originally put on. I was taught many moons ago that to be safe air tires to 10% of what the max. pressure is on the tire. This has worked for 40 years now.

Well, I'll admit I've never done that, I've alway's aired to max sidewall rated psi...never added an extra 10% which would be loading a Michelin "E" rated RIBS to 88# instead of 80 and airing my GY G614's to 121 psi instead of the recommended 110psi...one could do that, but again, I've been towing since 75, (and some before that), and also never had an issue... and thats worked for me for almost 40 years also...

My experience has seen most newer RV's with tires on them that are "just close" enough to cover axle rating...as little as the manufacturer can get away with and cut corners on cost. It's rare that I've seen a "G" rated tire where an "E" rated tire would have worked...it's very, very rare.

What he meant was 10% under the maximum pressure, not 10% over the maximum pressure. This was to allow the old bias ply tires to expand pressure from heat and keep them within a safe operating pressure. I also run 100 pounds in my tires that have a max rating of 110 pounds, my dad sold Goodyear & Atlas tires in the 60s and 70s and this is what I was taught. How this theory holds up today with radials I do not know, all I know for sure is that my dad still holds to this theory and it has worked well so I am continuing the tradition. Also, in the old school days, putting the next size bigger tire was also standard practice as auto manufacturers are notorious for putting marginal tires on their vehicles, it looks good on some draftsman's drawings, but in the real world, it hold no water--e.g. the tire debacle with Ford Explorers a few years ago, too small a tire for the weight of the vehicle caused lots of problems. That is why I changed my 8r19.5s for 245x70r19.5s, slightly larger in diameter, much wider foot print, and my mh handles much better. When my van gets new tires this winter, I will jump it 2 sizes 215x70r15 to 235x75r15 they 215s are toooooo small a tire for the weight of the van and at max pressure the sides are still wearing out faster than the centers.