Tire pressure ?

[TexasJeff]

Just a quick follow up... I talked to my son this morning. He's an auto mechanic... and I'm not going to say that he knows all there is to know... but he offered his opinion on my question posed just above.

The tires themselves will post maximum air pressure but the door jam tag will specify the recommended pressure for that particular vehicle. Just passing this along.

[jrollf]

Originally Posted by TexasJeff

Just a quick follow up... I talked to my son this morning. He's an auto mechanic... and I'm not going to say that he knows all there is to know... but he offered his opinion on my question posed just above.

The tires themselves will post maximum air pressure but the door jam tag will specify the recommended pressure for that particular vehicle. Just passing this along.

This is correct, the Tire Engineer says the same thing on the website I posted earlier.

Door jamb sticker = Minimum cold pressure to carry the GVWR rating of the vehicle.

Tire pressure rating = Minimum cold tire pressure to carry the max rated load of the tire.

If the GVWR puts a smaller load on the tire than it is capable of carrying, the vehicle manufacturer will usually list a lower tire pressure than the tire is marked for. It's all a balance of safety, tread life, load capacity, and smoother ride.

What often happens with Travel Trailers/RV blow outs, is people overload trailer/RV and don't realize it and just run the pressure on the sticker, not the pressure on the tire. So you end up with tires that are overloaded for the pressure they are set at, then they overheat and blowout. This is why a lot of people will say to error on the safe side and run at the tire's pressure rating for max load capacity, or somewhere between the Trailer/RV sticker and the tire rating. Running higher pressure than needed will help the tire run cool and reduce chances of blow out. The down side is the ride is rougher and you may wear the center of the tires a bit quicker if you are not overloaded.

[TexasJeff]

Originally Posted by jrollf

Running higher pressure than needed will help the tire run cool and reduce chances of blow out. The down side is the ride is rougher and you may wear the center of the tires a bit quicker if you are not overloaded.

I'm guilty of filling up, loading up, and heading out without too much attention to detail. Either it's going to catch up with me, or I'm going to be a little more cautious. Thanks and good to know the details!

[bneukam]

We put a lot of miles on our trailer. So we run per the tire manufacturers load chart, plus a little extra for safety.

Some can just run with the max, because a set of tires will age out before wearing out.

Most importantly we run with a TPMS

[cviv]

My 2020 Newmar BayStar Class A came from the dealer with tire pressure
set at MAX 110# PSI as stamped on the sidewall of all tires.
I reduced the pressure to 92# PSI the suggested GVWR sticker pressure inside the coach on all tires.
Then I had the coach axels weighed and the service tech set the pressure
to 80# PSI Rear and 70# PSI Front from tire mfg pressure table.

So my question is which tire pressure is closer to correct?

[Chowboy]

Originally Posted by TexasJeff

I'm not coming from a point of knowledge here so I want to ask more for clarification of my understanding than anything.

I had always thought that the inflation information on the sides of the tires were "maximum" cold tire pressure. Shouldn't you adjust your tire pressure to make sure your tire's wear is even across the tread but never exceeding that maximum pressure? Or does this line of thought only apply to passenger tires?

Most of us age out tires rather than wear out tires. Were these on the tow vehicle I might, probably not but might agree, were you to exceed 10,000 per year regularly I would agree. I doubt I have reached 20,000 in 4 years on any set and the tread has never displayed strange wear, and yes I am sure some sets were China bombs as will be future sets, providing our ports get working and I can find replacements.

[Atlee]

The placard on my 6000# GVWR says 65# of air in each tire.
They are Chinese Castle Rocks, but at least the trailer manufacturer did put on D range tires.

So, I air the tires up to 65#.

Originally Posted by jrollf

This is correct, the Tire Engineer says the same thing on the website I posted earlier.

Door jamb sticker = Minimum cold pressure to carry the GVWR rating of the vehicle.

Tire pressure rating = Minimum cold tire pressure to carry the max rated load of the tire.

If the GVWR puts a smaller load on the tire than it is capable of carrying, the vehicle manufacturer will usually list a lower tire pressure than the tire is marked for. It's all a balance of safety, tread life, load capacity, and smoother ride.

What often happens with Travel Trailers/RV blow outs, is people overload trailer/RV and don't realize it and just run the pressure on the sticker, not the pressure on the tire. So you end up with tires that are overloaded for the pressure they are set at, then they overheat and blowout. This is why a lot of people will say to error on the safe side and run at the tire's pressure rating for max load capacity, or somewhere between the Trailer/RV sticker and the tire rating. Running higher pressure than needed will help the tire run cool and reduce chances of blow out. The down side is the ride is rougher and you may wear the center of the tires a bit quicker if you are not overloaded.

[LeisurePursuits]

My trailer has Goodyear Endurance tires that have max load rating at 80psi. I was getting uneven and rapid tire wear. Goodyear has a chart that says for my GVWR (10,000lbs) and two axles that I should be running about 50 psi. I replaced a couple of tires that had excessive wear and now run 55 psi. Tires have thousands of miles since and the wear is much better. Factory GM trailer TPMS system shows normal tire temperatures. Bottom line is that you may not need to run at max psi and possibly your tires will wear better if you don't. YMMV. Do your research for your particular situation.

[KJLarson]

The psi indicated on the tire sidewall is the max psi the tire is designed to hold. The correct psi is dependent on the weight placed on the tire. Each tire manufacturer of ST and LT tires has a chart that indicates the correct psi under different load conditions. The one for Goodyear Endurance ST tires can be found at "goodyearrvtires.com/pdfs/rv_inflation.pdf".

As an example, my TT has a gross weight of 5,400 lbs. Since it a dual axel TT I have to divide the gross weight by four (4 tires) to determine the weight on each tire, or 1,350 lbs. per tire. Looking at the chart for my 215/75R14 tires I find that the correct psi is 30 lbs. less than half the max psi for the tire. Knowing this I can be assured that the entire tread width of the tire is on the pavement; a higher psi means that the tire is riding on the center of the tread width. That can lead to premature wear and poor handling especially in wet pavement conditions.

The weight load on each tire will vary depending on what I am carrying each trip; but; we generally load out the same so I use the 30 psi most of the time. Our TT does not have slide-outs which makes it easier to compute the correct psi. If your TT has slide-outs than it is best to have it weighed on a scale, weight each side independently because the side with the slide-out will be heavier and may require a higher psi in the tires on that side.

Load balancing in addition to correct psi is also important to get the best traction especially on wet or snowy pavement; that means everything from side to side and front to rear plus the tongue weight will affect the tires performance. Having the correct tire psi just may save your life or prevent injury to yourself and others.

[astrnmrtom]

Rather than entering the tire pressure debate which has been discussed many many times on this and other vehicle forums, I'll add one Caveat about inflating to the maximum listed on the tire. Unless you have the exact size and type of tire put on by the manufacturer, this could be problematic. If someone were to buy my rig and inflate the tires to the max on the sidewall, they'd be exceeding the maximum allowed pressure of my aluminum rims. I upgraded to the next larger size tire to give myself a little extra overhead since I'm hanging a motorcycle off the back. I go by weight and tire chart values +10% which is still below the max limit stamped on my rims.


People over think tire pressures way too much. You don't need to track temperatures on a daily basis, nor worry about altitude. Temperatures can swing by 20 degrees in a day. Just think of what it's like driving on a hot summer day in the mountains, then suddenly encountering a thunderstorm where the temps plummet and it starts raining a cold rain. That could really effect tire temperatures As mentioned above you wouldn't pull over and adjust the pressure. There's millions and millions of drivers that never think of their tire pressure until the TPMS, if they have one, lights up on the dash. If tires were that sensitive to daily fluctuation, they'd be blowing out left and right every day.

[bneukam]

Personally I feel the Goodyear load chart is a little too low, and prefer to have extra capacity. We run 50 psi, even though we could run 40 per the chart.

We installed them 9 months ago, and 7k miles later the tread is looking good.

[JIMNLIN]

Goodyears website in the part that talks about weighing your rv says ; Quote..

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.**

This thread is about air pressure in a tire on a trailer.
There is nothing in common in best tire pressures for a truck/car/SUV/motor homes/bus/etc vs best pressures for a tires on a trailer.