Tuesday, October 3, 2023


RV Tire Safety: RVer thinks 65 psi in TT tires is too much; asks for advice

By Roger Marble
“65 psi is too much” was the opinion posted on an RV Tips Facebook page by Tom. He said: “OK, I can’t find any info here so one last time. The tire pressure says 65 psi cold on the sidewall of the tires on my travel trailer. That sounds like a lot to me. What tire pressure do you run your camper at?”

I’m not sure where he did his search. On the FB page, he did get some answers such as “60” and “110” and “80”.

I responded:

As an actual Tire Design Engineer, with 40 years of experience including decades of trailer ownership, I can explain why you need to follow the Science of proper tire loading and inflation.

You have a Certification sticker or label on your travel trailer that was applied by the RV company based on safety regulations. The sticker tells you the correct information for tire size, type, and Load Range. It also tells you the GAWR (Gross Axle Weight Rating). You should not exceed the GAWR because you can break wheels, bolts, axles, hubs, springs, and related parts. Known strength limits of these parts were used to establish the maximum load you should put on your axles.

The tire industry has tables that cover the dimensions and load limits for tires for different levels of inflation. These tables have been around since the ’70s. All tires sold for highway use in the U.S. are required to be capable of passing a number of different strength and durability tests. The test conditions specify both load and inflation levels for the different tests.

The RV company has the responsibility to provide the information on the certification sticker such that the specified tires are rated to support at least 110% of GAWR when they are inflated to the stated inflation when the tires are at Ambient Temperature, i.e., “cold”.

You didn’t offer what tire engineering experience you bring to this discussion, so I don’t know how you arrived at your conclusion that 65 psi cold (ambient) was “too much.” But I sincerely doubt that the RV company would select LR-D tires if that level of load capacity was not needed.

You can learn more about tires by reading some of the 500+ posts on my blog: RVTireSafety.Net or at RVtravel.com.



Roger Marble
Roger Marblehttp://www.RVTireSafety.net
Retired Tire Design and Forensic Engineer w/50+ years of experience. Currently has Class-C RV. Previous Truck Camper, Winny Brave, Class-C & 23'TT. Also towed race car w/ 23' open trailer and in 26' Closed trailer. While racing he set lap records at 6 different tracks racing from Lime Rock CT to Riverside CA and Daytona to Mosport Canada. Gives RV and Genealogy Seminars for FMCA across the USA. Taught vehicle handling to local Police Depts


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1 year ago

As a lifetime driver of commercial vehicles with a GVWR of 80,000+ lbs I can tell you 65psi doesn’t seem high at all!

1 year ago
Reply to  Mike

Keep your air pressures up and brakes in adjustment keeps dot happier.

1 year ago

The person asking the question read the recommendation off of the tire. We do not know that the tire is the correct one for the trailer. This should be determined as suggested, by checking either the owners manual, manufacturer’s website or the trailers data plate, then inflate to the recommended pressure from the manufacturer. Frequently trailer tires are replaced with car or truck tires which is unsafe practice. Tires labeled “trailer use” should only be used as their construction and pressure ratings are designed for this specific use.

1 year ago

How could the sticker on the vehicle know your particular weight. A passenger car might have a relatively close min max, but my toy hauler loaded has 2000 lbs more than empty. A semi truck trailer far more. One time I found a tire mfg website said to fill until the axle center was a certain height above the ground. That seemed like the best way to compensate for loaded, unloaded. I can’t find that spec anywhere now. A website for my bfg all terrains said to drive through powdered chalk and make sure there is a half inch of “unchalked” at the side of the tire. That also seems like a way to compensate for load. I lower my tire pressure on my truck and trailer when using unloaded. I’m aiming for even wear.

1 year ago

As a retired truck driver/ mechanic I’ll tell you that you always go by the vehicle tire sticker. Tire inflation is based on the weight of the vehicle. The heavier the vehicle the higher the pressure. You never go by what’s on the tire. That’s the tire manufacturer saying hey don’t go over this pressure but that tire can go on many vehicles of different weight. RV manufacturers know by the table the proper pressure so listen to them and their sticker. To give you an example an 18 wheeler the front tires are 95 psi and rear tires 105 psi. Again don’t go by what’s on the tire, find the tire sticker on the vehicle. It might be in a doorway, under a basement door, under the hood but it’s there somewhere and it’s less than what’s on the tire. Do that and you’ll have even tread on the road surface and your tires will last longer.

Holiday Rambler Endevour
1 year ago

Give the guy a break. Lots of people have zero experience with truck or trailer tires designed for heavy loads. I know that I am not as knowledgeable about tire design and inflation requirements as the company making the tires, therefore the recommended pressure listed on the tire is probably what it should be inflated to. One thing that I have trouble wrapping my head around is the dual or single weight capacity and inflation requirements. Why 65psi single and 80psi dual? Is it just to keep the sidewalls on duals from touching? That inflation pressure also lowers the weight capacity rating per tire. I am smart enough to know it’s best to follow the recommendation of people who know more about the subject than myself. FYI 235/85R16 E is the specific tire size I’m referring to.

Robert Collins
1 year ago

My 22.5 michilen call for 110 lbs.
Read the sisldewalls.

1 year ago
Reply to  Robert Collins

Wrong answer.

Steve Hericks
1 year ago

LOVE IT! Great response. I’m an engineer and am so tired of debunking BS posts. Load inflation tables are always the right answer which also infers you measure/know your axle loads….everyone wants a simple answered when the ‘right’ answer rarely is.

1 year ago

I know you love getting tire or any other advice from someone who 2 weeks earlier was asking “Would you like fry’s with that order”. I’ve meet 100’s of people giving advice that you wonder how they can figure out how to put food on the table let alone how to fix something way over their heads.

1 year ago

As in all things mechanical, there’s always someone who knows better, and in this case doesn’t realize there is a manufacturers sticker sharing those little details. If he even has a tire gauge, it probably came from the 99 cent rack near the cash register. And a torque wrench? Waste of money. I got me a cheater bar, so them lug nuts stay tight.

1 year ago

65 PSI is twice the pressure he puts in his car tires and he’s been driving for twenty years. So 65 must be too much.

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