Tires rated for 95 psi sidewall - ok to run 80psi?

Jhurk wrote:
I purchased a 2009 Cardinal had them change tires as 8 yrs old. ST 235-80-16 were stock tires recommend 80psi for max load for rim of 3100 lbs. they changed tire and put on ST 235-85-16 max on sidewall of 95 psi and for load 3800 lbs. I went to,tire dealer to see if I could run them at 95 psi on the rims. They said run them at 80 psi and that would be fine good for 3200 lbs per tire. I had them put in steal valve stems and balance tires. Question is,would I,be ok with 80 psi. That is more tan enough for the weight so I,believe it would be ok?

OK?? Probably, but experts say run STs at max pressure, for cooler running, less flex, scrub, etc. If wheels are only rated to 80 psi, I would not air to 95 psi. IMO, it makes no sense to over tire, then lower pressure, to work with lower rated wheels, when the OEM E rated tires are adequate, and lasted 8 years, with no issue.

I know tire dealers like to sell what they have on hand, but I would have requested ordering the proper tire, or looked elsewhere.

Jerry

Over tiring a trailers wheels/axles and figuring what pressures to run is a hot topic. More tire may not be the best idea depending on loads and pressures from other components.
The benefit of the F tires over a E tire 80 psi come only at those higher 95 psi numbers.

Minimum pressure load charts are just that and work well with a truck/van/suv/motorhome with tires at the corners but not the best idea in the trailer world where the axles are close together and in the center of a heavy vehicle where loads are changing constantly while going down the road.
Loads on a trailer tires can change especially in strong side winds or road surface crowns.
Now add ply shearing issues when turning a corner. Max pressures insures cooler operating and the tire can hold its shape better than a derated tire with low pressures.
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rvsafety.com

Tire Load and Inflation Ratings

Note: Towable – Travel Trailer/ 5th Wheel owners Due to the severe use conditions experienced by tires when axles are very close together – tire industry experts recommend maximum (sidewall) inflation pressure for towable tires unless this causes a sever over-inflation situation (20psi+), often referred to as the ‘basketball effect’. If this is your situation allow a 10 – 15psi safety margin above the minimum required inflation pressure.

I would look at the rim and make sure it is rated for the pressure.

Don't ST tires require full inflation pressure?

Probably but the safe answer is to weigh it fully loaded and look up the mfrs recommendation for that weight then add 5 PSI.

Many tire makers publish load vs inflation charts. Lower weight on tires corresponds to lower required pressure. As long as those numbers correspond to their chart there would be no problem.

Yes.