Tire Pressure

[kjohn6363]

Should tire pressure be what is recommended on the tire or what is
recommended on the 5th Wheel Plaque?

[Carl n Susan]

Both the tire and the plaque list maximum pressure. They should be the same and what you you should use.

[rohrmann]

It depends. What year and model rig do you have? Also, do you know what is stamped on the back of the wheels, probably have to take one off to see the markings? Our rig came with 10 ply tires, rated pressure was 80 psi, and that is what is needed on the tag at the left front corner of the rig. The wheels are rated to 110 psi, and after having five tire failures, but no blow outs, we upgraded to the tires that were optional for the rig, 14 ply, 110 psi, so I keep them close to 110 psi, not what the label on the rig says. Generally, if the wheels can take the pressure, you will get the full weight capacity of the tires if they are inflated to the maximum cold inflation pressure that is on the sidewall. Some will say weigh the rig and only put enough air that will support the weight at that pressure. It’s up to you.

[kjohn6363]

Just put Salium ST 235/80 R16 G-rated 14ply on my 2019 High Country
PSI is 110

[mlh]

If you have 80 pound rims 80 pounds. If you have 110 pound rims there is no reason not to run at 110 pounds.
Lynwood

[phillyg]

Here we go again. What's on the tires is the max psi for that tire, and the sticker is what the RV mfgr. has computed to be the proper psi, which may not be accurate in the real world. Psi should be set by you when the tire is cold, i.e., not driven on, regardless of ambient temps, and should never be aired over the stated max, and can be adjusted downwards once you know (weigh) your actual load.

Some folks erroneously say, with great conviction, that ST tires must always be set at max psi. While it's true they can be set at max, it's not required, as ST tire mfgrs. publish load tables so you can adjust psi accordingly. For example, on a 7000lb axle using tires rated for 4400lbs each at 110psi, the best psi might be whatever the mfgr. calculates for only 3500lbs each, could be 80, could be less, depending on the actual weight on that axle. Arbitrarily airing to max psi can unnecessarily increase wear and tear on the running gear, and shake the heck out of your trailer contents, but do as you want.

[CalandLinda]

Originally Posted by kjohn6363

Should tire pressure be what is recommended on the tire or what is recommended on the 5th Wheel Plaque?

The correct inflation pressures for OE tires is displayed on the vehicle certification label, tire and loading placard and in the vehicle owner's manual.

Replacement tires must provide a load capacity equal to or greater than what the OE tires provided via cold inflation pressures.

The PSI displayed on all tire sidewalls is the pressure necessary for the tire to provide its maximum load capacity.

The USTMA says to NEVER use inflation pressures below what has been recommended by the vehicle manufacturer.

Inflating RV trailer tires to the load carried IS NOT a FMVSS standard. It's from the trucking industry standards (FMCSA) and is not applicable for RV trailer tires.

Load inflation charts are not recommendations. They are used by tire installers so they can determine a proper load capacity via inflation pressures that will allow them to set a a proper cold inflation pressure. The charts are most helpful when the installer is determining new cold inflation pressures for larger "plus sized" replacement tires.