Replacement Tires

[CALinSC]

Originally Posted by Cummins12V98

Not sure your point. I posted EXACTLY what GY tech Support told me to do if wanting to use the Tire weight/inflation charts instead of BLINDLY running MAX inflation.

This is for up sizing load range or if you have a RV that has PLENTY of tire capacity to run less than MAX.

I'm often misunderstood when posting about RV trailer tires. My information comes from government regulations and established tire industry standards.

RV trailer tires are any size and design the trailer manufacturer deems appropriate for that application.

RV trailer tires are governed by FMVSS (standards) and tire industry standards (ONLY!). FMCSA Regulations are not applicable with FMVSS.

So the inflation pressures found on the tire vehicle certification label are correct and minimum. Problem is, with RV trailers in the past there has hardly ever been any wiggle room as the vehicle manufacturers have fitted tires to your trailer with (sometimes) the very minimum required. Newer RV trailers will have a 10% increase in load capacity above the trailer's vehicle certified GAWRs.

The tire industry sticks by the vehicle manufacturer's original equipment tire load capacity. The do that with their canned statement found everywhere and goes like this. "Replacement tires MUST have a load capacity equal to or greater than the OE tires." Meaning by inflation.

Using replacement tires that do not conform to the OE tires load inflation chart are considered "plus sized tires." Once a new recommended tire inflation is determined for the plus sized tire it becomes the new minimum. The USTMA will allow any inflation pressures between recommended and tire sidewall max as OPTIONAL with the caveat, "Never use inflation pressures less than recommended minimum or what's on the vehicle certification label."

I can provide references if needed. They will be from FMVSS & USTMA.

Bridgestone/Firestone have a replacement tire PDF available on line that explains the procedures in much more depth and from the installers point of view. I don't keep such references once I have memorized the basics.