My take on how to treat MH tires

[TireHobby]

This is sort of a “pro-con” post or just plain old logic, laced with governing body/tire industry facts as they are presented in numerous reference materials found on the WWW.

 

From a previous statement.

 

“It is important to remember that by law the inflation on the sticker must provide sufficient load capacity to carry the GAWR for each axle.”

 

This is what one of the regulations says. IMO appropriate is often used to stress that other factors are at work on the fitment in other parts of the regulations. But, the meat is in the statement about tire inflation. Without recommended tire inflation pressures tire pressures would be at the whim of whoever wants to set them. NHTSA has given the sole responsibility for Original Equipment tire inflation pressures to the vehicle manufacturer.

 

“FMVSS No. 120 requires that each vehicle show, on the label required by 567.4, or on a tire information label (S5.3.2), the recommended tire size designation appropriate for the GAWR, the size and type designation of rims appropriate for those tires, and the recommended cold inflation pressure for those tires such that the sum of the load ratings of the tires on each axle is appropriate for the GAWR.”

 

Also from the previous statement.

 

“So if you are significantly under the GAWR then clearly you do not need to run tire pressure needed to carry the GAWR.”

 

That’s sort of wishy-washy. Tire industry standards never recommend using lower tire inflation pressures than what is recommended on the tire placard for OE tires.

 

When new tire industry rules are written the governing body and representatives from the tire industry get together and hash over the proposals and in the end new rules are written and made into law. During the last major rules making session’s discussion phase, one of the factors discussed was tire inflation pressure loss. One of the facts presented was that for every single psi loss there is a 1.6% loss of load capacity. Since that session, many of the major tire manufacturers no longer recommend inflation pressures to equal the load carried. That rule’s debate was in 2007 and the document can still be found on the WWW for review, it’s quite lengthy.