Tire Inflation, Again!

[FastEagle]

A brief quote from NHTSA.

"Industry standards generally form the basis for demonstrating product safety and quality before courts, regulators, retailers, consumers and others."

[Bob Hyatt]

I thought what he posted made perfect sense. A tire manufacturer can NOT give us a recommended cold inflation level, ONLY a max level beyond which tire destruction is likely. How to inflate tires is independent of coaches vs trailers vs automobiles. ALL follow the same rules. Most tire manufactures do provide load-carrying capabilities at various inflation points, up to the max. But getting that right requires a scale. So what is your problem with his comments??? Too little and you wear the outer edges excessively, too much and you wear the center excessively. How could a tire manufacturer have any idea of what loading is going to land on any one tire when the load range for the tires can vary significantly?

BTW I think you misunderstood what he wrote. He simply said that in ALMOST ALL cases, specifications are made for lawyers, rather than for consumers. If the manufacturers were all specifying a recommended inflation level, everyone would be running 44psi or so on a car tire and tolerating every crack in the road rattling their spine...

[TripleEEE]

Originally Posted by Bob Hyatt

I thought what he posted made perfect sense. A tire manufacturer can NOT give us a recommended cold inflation level, ONLY a max level beyond which tire destruction is likely. How to inflate tires is independent of coaches vs trailers vs automobiles. ALL follow the same rules. Most tire manufactures do provide load-carrying capabilities at various inflation points, up to the max. But getting that right requires a scale. So what is your problem with his comments??? Too little and you wear the outer edges excessively, too much and you wear the center excessively. How could a tire manufacturer have any idea of what loading is going to land on any one tire when the load range for the tires can vary significantly?

BTW I think you misunderstood what he wrote. He simply said that in ALMOST ALL cases, specifications are made for lawyers, rather than for consumers. If the manufacturers were all specifying a recommended inflation level, everyone would be running 44psi or so on a car tire and tolerating every crack in the road rattling their spine...

^^^ That's how I took it as well..........

Great first post and welcome to IRV2.

[bdickson]

Folks, please refrain from bickering and personal attacks on other members, and discuss the topic of the thread in a courteous manner. Some posts have been deleted and may continue to be deleted without notice. Thanks.

[Sonic]

Originally Posted by Bob Hyatt

I thought what he posted made perfect sense. A tire manufacturer can NOT give us a recommended cold inflation level, ONLY a max level beyond which tire destruction is likely. How to inflate tires is independent of coaches vs trailers vs automobiles. ALL follow the same rules. Most tire manufactures do provide load-carrying capabilities at various inflation points, up to the max.

Maybe I'm misunderstanding, but Michelin DOES recommend cold tire pressure based on weights at each wheel using the heaviest weight per axle.
From their website:

"Michelin displays tire loads per axle end in the load and inflation tables. We recommend weighing each axle end separately and using the heaviest end weight to determine the axle's cold inflation tire pressure. For control of your RV, make sure tire pressures are the same across an axle, while NEVER exceeding the maximum air pressure limit stamped on the wheels."

The chart then gives the recommended cold tire inflation based on the axle weight (heaviest position weight on that axle)

https://www.michelinrvtires.com/refe...tion-tables/#/

[FastEagle]

Michelin likes to assume that readers of their PDFs have a full understanding and knowledge of all tire industry standards. So they don't always include a full explanation. Here are excerpts from such a document.

The vehicle manufacturer selects the size and type of tires for their vehicles. They perform the necessary testing to establish the vehicles’ optimized operating tire inflation pressures which can be found on the vehicle placard (located on the inside of the driver's door) and in the vehicle owners’ manual.

If the tires on your vehicle are the same size as the original equipment tire, inflate them to the pressures indicated on the placard.

When installing a different size than the original equipment tire, all vehicle manufacturer specifications must be maintained. The replacement tire should be inflated to provide the same load capability of the original tire size at the manufacturer’s recommended pressure.

NOTE: Tire industry standards say to NEVER - under normal circumstances - use less tire inflation pressures than what has been recommended by the vehicle manufacturer. Anything between recommended and sidewall max is optional.

[MDPD]

I really don't understand why we continue to beat a dead horse over this issue. The pressure on the placard takes into account the ability of the tires to carry the total combined gross vehicle weight of the motorhome to cover the manufacturer. Michelin and I am sure other companies post charts for the proper inflation based on the actual weight carried as determined by weighing as it will be used. The Recreational Vehicle & Educational Foundation RVSEF, whom I have used several times, has weighing stations and will help determine the correct pressures per the tire manufacturers charts after performing the weighing and adding 5%. (Check out their web site) If you want to save the $60 for weighing, use the placard pressure (you can't go wrong unless you are overloaded) and deal with the harsher ride, tire wear, and handling issue from over inflated tires OR deal with the consequences of the actual weight being over the capacity of the tires and or chassis. Your choice, my opinion