# Trailer Tire Pressure



## barbara odonnell (Jun 4, 2005)

Probably a dumb question, but in my husband's absence this evening, I'd like to correctly inflate my 2005 21RS tires for our first outing tomorrow. Tire says max of 50 PSI. What's recommended for a trailer that's not overly loaded with cargo?


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## Ghosty (Jan 17, 2005)

I keep my tires right at 45 - 50 all the time. More pressure equates to less heat and stiffer walls (less sway) ...


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## barbara odonnell (Jun 4, 2005)

Thanks. They are currently at 45, but I thought they may have lost pressure in storage over the winter. Sounds like they are just fine. ...Barb


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## dak (Jan 17, 2005)

This may be stating the obvious, but...

Make sure the tires have had time to cool down. Don't check the pressure as you pull into the gas station. Let them sit for a few hours or overnight. The air in the tires needs to be the same temperature as the air outside the tires, otherwise your pressure readings will be off. I've seen too many people ruin tires and/or have accidents because they thought they were doing it right but weren't.

dak


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## c_rad91 (Feb 18, 2005)

Just curious...what does the tire say the max pressure is. Mine are 15" tires and the max pressure is 65 psi. The dealer set them at 45 psi and I actually towed at that the first time out because I assumed they would have them set properly. I pushed them up to 65 psi before the second trip. Under-inflation, as previously stated by Ghosty leads to more heat and possibly premature tire failure. My trailer gross is 10K and each tire is rated at 2540# at max pressure. I would run them at max pressure when loaded.


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## MJRey (Jan 21, 2005)

You should always run trailer tires close to the maximum pressure for the rated load. For a load range C tire that is 50psi (cold) and for a load range D it's 65psi (cold). Tire load capacity decreases as the pressure drops from the max load pressure due to tire sidewall flexing which generates heat. These tables from Goodyear give an idea of how much capacity you loose as the pressure drops. The first table is the one for most trailer tires:

http://www.goodyear.com/rv/pdf/rv_inflation.pdf

For the ST205/75R14 tires and the weight of the 21RS you'll be fine at 45-50psi.


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## CamperAndy (Aug 26, 2004)

What Mark said is the way to go. Set them at MAX for the tires you have and let her roll.

You can loose 5 psi over the winter and that is no problem. Just top them up before you take a loaded trailer on a trip.


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## Thor (Apr 7, 2004)

CamperAndy said:


> What Mark said is the way to go. Set them at MAX for the tires you have and let her roll.
> 
> You can loose 5 psi over the winter and that is no problem. Just top them up before you take a loaded trailer on a trip.
> [snapback]39120[/snapback]​


I check everytime before I head out, just to make sure I have the proper tire pressure. It only takes a few seconds and it is very easy to do.

Thor


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## tdvffjohn (Mar 10, 2005)

I also check TV and trailer every time out, at the same time as oil and trans.

John


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