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

[Jhurk]

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?

[Cummins12V98]

Per GY Technical Support when going up in capacity as in "E" to "G" they recommend weighing your RV's tires, each if possible. Take the heaviest tire per axle compare to the weight inflation chart and add 5psi to what it calls for. Example my 02 AVION had "E" tires and I ran 80psi, comparing to the chart I needed to run 80. I upgraded to GY "G" and using the chart it said 80 so I added 5 psi. I ran those tires at that psi for many thousands of miles with perfect tread wear and nice ride. No I did NOT have 110psi rims as I did not need them.

[Retired_VSP]

Thank u....I think I'll back psi off quite a bit

[Cummins12V98]

Retired VSP wrote:
Just had GY installed today...sidewall says 110 psi ... G rated...had F rated and ran 80 psi....tire techs put 100 psi...riding rough....can I back off a little?

I ran GY G's for thousands of miles with perfect tread wear at 85psi using weight/inflation chart.

[JIMNLIN]

Goodyear Tire and Rubber .... weighing RVs
Special Considerations

*Unless trying to resolve poor ride quality problems with an RV trailer, it is recommended that trailer tires be inflated to the pressure indicated on the sidewall of the tire. Trailer tires experience significant lateral (side-to-side) loads due to vehicle sway from uneven roads or passing vehicles. Using the inflation pressure engraved on the sidewall will provide optimum load carrying capacity and minimize heat build-up.*

We have lots of tire blogs on the net and the ones that speak with experience goes much like this one;

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.

[Retired_VSP]

Just had GY installed today...sidewall says 110 psi ... G rated...had F rated and ran 80 psi....tire techs put 100 psi...riding rough....can I back off a little?

[Cummins12V98]

On my 02 Avion I had "E" 80psi GY Wranglers the rims were 80psi rated. Based on my actual weight my tires were maxed out. I changed to GY "G" tires and the chart said 80psi based on my weight so I ran 85 per GY Tech support. I ran those tires for 4 years and thousands of miles with perfectly even tread wear. The 80 psi rim rating has a safety factor, they don't magically explode a few psi higher.

[MFL]

eHoefler wrote:
When it came time for me to replace our tires, I researched many different ways to go. I wound up purchasing 17.5" J rated medium duty truck tires and wheels. When all done and said, it was $5.00 per wheel and tire combo more than just replaceing the 16" tires. This tire and wheel combo is good for 6005 pounds each. Using the inflation chart to get the pressure for the load, I inflated to 80 psi which was good for 4500 pounds per tire. With the first tow with these tires to Kansas City, I have made this trip to the speedway several times before, I was down almost 2 mpg both ways. The tires were 20*-25* hotter than the truck, which I have never wxperienced before. I inflated them to the side wall pressure, 125 psi for max load, before our trip to Florida. Now the tires run 5*-10* cooler than the truck and my fuel mileage is back where it used to be. I have always run max pressure up until I installed these tires, with what I have experienced, I will continue to run what the side wall indicates.

Thanks for giving a good report/example of what I have been saying about over tiring, then reducing pressure. Smart move, to get proper wheels to go with the 125 psi tires. You have a big rig, that can use those HD tires/wheels at full pressure.

Jerry

[eHoefler]

When it came time for me to replace our tires, I researched many different ways to go. I wound up purchasing 17.5" J rated medium duty truck tires and wheels. When all done and said, it was $5.00 per wheel and tire combo more than just replaceing the 16" tires. This tire and wheel combo is good for 6005 pounds each. Using the inflation chart to get the pressure for the load, I inflated to 80 psi which was good for 4500 pounds per tire. With the first tow with these tires to Kansas City, I have made this trip to the speedway several times before, I was down almost 2 mpg both ways. The tires were 20*-25* hotter than the truck, which I have never wxperienced before. I inflated them to the side wall pressure, 125 psi for max load, before our trip to Florida. Now the tires run 5*-10* cooler than the truck and my fuel mileage is back where it used to be. I have always run max pressure up until I installed these tires, with what I have experienced, I will continue to run what the side wall indicates.

[Jhurk]

Cummins12V98 wrote:

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

EXACTLY!!!

That's not the question the question is, is it safe to put in 80psi in a tire rated for max 95 psi. Consider the load rating for 80 psi is ok. The rim I have is only rated for 80psi and the tire mount ed is rated for 95. Tire tech says I'm fine.

[Cummins12V98]

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

EXACTLY!!!

[MFL]

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

[JIMNLIN]

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.
...............................................

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.

[eHoefler]

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

[dalej]

Don't ST tires require full inflation pressure?