Tire Pressure Chart

[LOG]

I wonder why Gary RVRoamer and Tireman9 have not posted on this thread. Their knowledge and experience would go a long way to help Forum Members on this subject. After all, it has had over 1500 views.

[Bill Gail]

When I submitted this thread , I had no idea it would generate the passonite and vigerous discussion it has.

I truly appreciate everyone's participation and I want to specifically thank both LOG and FastEagle for their valued input.

If there is anyone reading this thread with more information to share regarding this issue , please join in the discussion.

The great thing about our forum is the vast knowledge and experience our members can and do provide.

[FastEagle]

Originally Posted by Bill Gail

What I was attempting to do by starting this thread was to gain insight on tire pressure relationship to handling and ride quality . I personally have experienced a positive result by setting tire pressures to actual loads.

While I agree with LOG on this issue and am concerned that FasrEagle is potentially putting members and loved ones at risk. I would appreciate inputs on where I did that so I can retract it or clear it-up.

I strongly recommend members do their own research and come to your own conclusions .

My research showed that the tire pressure to load relationship was an established science. (Then why would NHTSA insure there are load capacity reserves for automotive tire fitmants?)

Don't take anyone's opinions as fact on any subject , especially something as important as Safety. (I don't write opinions without saying so.)

Take care and be Safe.

If there are errors in tire regulations, NHTSA has a site where they can be addressed and corrected, if necessary.

Please remember this is a two dimensional medium. If you were in my classroom, you would see that I'm being sincere with my postings on this subject.

[Bill Gail]

My statement speaks for itself . There is a POTENTIAL risk .

When running tires in an overinflated condition it is as dangerous as running the tires underinflated.

What I have gathered from your position is that the tires must always be set at maximum axle weight psi , regardless of load.

I respectfully disagree .

I do agree that if running at near or at maximum axle weight the psi on the placard is the correct psi .

Your position that the placard states a mandatory psi regardless of load is an interpretation .
If the vehicle tire psi should not be adjusted for load ( not to exceed max axle weight but to adjust for lighter loads) it would be included and clearly stated on the placard .

I'm sure you disagree . Looking forward to your response.

[FastEagle]

Originally Posted by Bill Gail

My statement speaks for itself . There is a POTENTIAL risk .

When running tires in an overinflated condition it is as dangerous as running the tires underinflated. Overinflated is above tire sidewall max. Underinflated is below vehicle manufacturer cold recommendations.

What I have gathered from your position is that the tires must always be set at maximum axle weight psi , regardless of load. The correct inflation pressures is what's displayed on the vehicle certification label. Those inflation pressures are what the vehicle manufacturer determines as appropriate for those tires on that vehicle. As the vehicle owner your adjustment options fall between what has been recommended and sidewall max.

I respectfully disagree .

I do agree that if running at near or at maximum axle weight the psi on the placard is the correct psi .

Your position that the placard states a mandatory psi regardless of load is an interpretation. The placard pressures are not maximum pressures. They are predetermined pressures appropriate for that fitment.

If the vehicle tire psi should not be adjusted for load ( not to exceed max axle weight but to adjust for lighter loads) it would be included and clearly stated on the placard . Yes it would and the picture below shows just how the vehicle manufacturer can do it if they decide it's the thing to do. No one else has that authority.

I'm sure you disagree . Looking forward to your response.

[LOG]

Originally Posted by FastEagle

In the reference attached below, scroll down to page #44 and read the information in the paragraphs under the header - Determining Proper Inflation Pressure.

Bottom line; never use inflation pressures below vehicle manufacturer recommendations.

https://www.ustires.org/sites/defaul...TruckTires.pdf

This is, I believe, a policy position adopted by the Tire Manufactures Association to CYA (cover your ….) and try to limit tire manufactures liability. I believe that Michelin (not yet proven) has adopted that CYA policy. The problem is that the policy contradicts the information provided in their RV Tire Publications. It also appears (not proven) that FASTEAGLE has or has had an association with the tire industry/tire manufactures and has adopted their polices. FASTEAGLE stated that he lives 10 miles from the Michelin Tire plant and talks to them often.
I have contacted the USTMA to inquire as to what basis they have for that policy. If it is based on Regulations. They have said they will get back to me.
I have also opened a case with Michelin Customer Care to resolve the contradictions with that policy and their RV Tire Publications.
I will report to the Forum when I hear from those two entities.

[FastEagle]

Originally Posted by LOG

This is, I believe, a policy position adopted by the Tire Manufactures Association to CYA (cover your ….) and try to limit tire manufactures liability. I believe that Michelin (not yet proven) has adopted that CYA policy. The problem is that the policy contradicts the information provided in their RV Tire Publications. It also appears (not proven) that FASTEAGLE has or has had an association with the tire industry/tire manufactures and has adopted their polices. FASTEAGLE stated that he lives 10 miles from the Michelin Tire plant and talks to them often.
I have contacted the USTMA to inquire as to what basis they have for that policy. If it is based on Regulations. They have said they will get back to me.
I have also opened a case with Michelin Customer Care to resolve the contradictions with that policy and their RV Tire Publications.
I will report to the Forum when I hear from those two entities.

I've been involved with government regulations all my adult life. They are very hard to explain to those that do not study them.

First there are precedents. When a document is senior, like in the case of CFRs (Code of Federal Regulations) others written later in the chain must comply with the older document for just as long as it's active. The (DOT) Department of Transportation farms out overall responsibilities to various departments such as NHTSA (National Highway Traffic Safety Administration).

NHTSA has tasked two departments, the FMCSA (Federal Motor Carrier Safety Administration) and FMVSS (Federal Motor Vehicle Safety Administration) with the overall responsibility of insuring all motor vehicles conform to national established safety standards. Each have their own specific rules for the vehicles they write standards for. Although they are separate departments and their rules are not applicable with each other they MUST do the look back.

All of our automotive vehicles come under the guidance of FMVSS. Vehicle certification is a CFR document. It MUST be complied with because that's the only way a motor vehicle will get certified to operate on our highways.

FMVSS are minimum standards. When they comply with vehicle certification they are setting a minimum standard because that's the only way the CFR will read it.

The FMVSS told vehicle manufacturers how to certify their vehicles. They are a minimum standards organization. Your vehicle certification label is in fact acting as a signature from FMVSS that it complies with all safety standards in effect on the day of certification. Minimum standards again. BOTTOM LINE: The tire industry is not going to try to trump - so to speak - the FMVSS in any way.

[LOG]

Originally Posted by FastEagle

I've been involved with government regulations all my adult life. They are very hard to explain to those that do not study them.

I simply consider myself an RVer.
But in my working life, I was an auditor with four different Federal Office of Inspectors General. I was not with the Department of Transportation Office of Inspector General. But where I worked we did the same thing they do, we audited compliance with Federal Regulations. We audited the Federal Agencies, and we audited any entity that interacted with them. Civilian groups or other Government groups. I once had the title of Assistant Regional Inspector General. I retired as a Federal Auditor.
I have a good understanding of Federal Regulations.
With that background, that is why I questioned when you said and continue to say that the USTMA policy is a Federal Regulation.
The tires, air pressure to support a load, are based on Federal Regulations.
The rims are based on Federal Regulations.
The tire Placard is based on Federal Regulations.
The tires fitted to support the axels are based on Federal Regulations.
The policy of how much air to put it the tires on a Motorhome after it is sold to a consumer, is not a Federal Regulation.
It is a recommendation. Pure and simple.
I have given you ample opportunities to support your statements and positions. All I get are your interpretations of applications of Federal Regulations.
It does not work like that. It is either a Regulation or it is not.

[FastEagle]

Originally Posted by LOG

I simply consider myself an RVer.
But in my working life, I was an auditor with four different Federal Office of Inspectors General. I was not with the Department of Transportation Office of Inspector General. But where I worked we did the same thing they do, we audited compliance with Federal Regulations. We audited the Federal Agencies, and we audited any entity that interacted with them. Civilian groups or other Government groups. I once had the title of Assistant Regional Inspector General. I retired as a Federal Auditor.
I have a good understanding of Federal Regulations.
With that background, that is why I questioned when you said and continue to say that the USTMA policy is a Federal Regulation.
The tires, air pressure to support a load, are based on Federal Regulations.
The rims are based on Federal Regulations.
The tire Placard is based on Federal Regulations.
The tires fitted to support the axels are based on Federal Regulations.
The policy of how much air to put it the tires on a Motorhome after it is sold to a consumer, is not a Federal Regulation.
It is a recommendation. Pure and simple.
I have given you ample opportunities to support your statements and positions. All I get are your interpretations of applications of Federal Regulations.
It does not work like that. It is either a Regulation or it is not.

Looking back I cannot see where I implied or said the USTMA was/is federal. Until recently they were the RMA (Rubber Manufacturers Association). They and the TRA (Tire and Rim Association) have a great deal of influence in developing and implementing our tire rules and regulations. If you pull up a tire rules committee document you will see they are always members of such committees.

You are interpreting the recommended in recommended cold inflation pressures wrong. It cannot be an absolute because of other factors such as temperature and altitude pressures. Besides that, SAFECAR – a NHTSA document – specifically states it’s the correct tire inflation pressure. (Options between what is recommended and tire sidewall max are at the desecration of the consumer).

I see a regulation as being a complete document and a standard as being part of a regulation.

We, as in citizens of the USA, have an obligation to follow a set of safety standards, enforced by a specific law or industry standard. Because the subject was always attacked in many of my tire posts I went to the NHTSA link that provides interpretations. This is what I got with my query about industry standards.

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

The TRA provides standardizations for tire designated sizes and the USTMA tells us to not use inflation pressures below what has been recommended by the vehicle manufacturer.

Third party tire testing standards are accepted by NHTSA.

NHTSA mandates vehicle owner manual safety inclusions in vehicle owner manuals. Here is one of them – “To maintain tire safety, purchase new tires that are the same size as the vehicle’s original tires or another size recommended by the manufacturer."

[LOG]

Originally Posted by FastEagle

In the reference attached below, scroll down to page #44 and read the information in the paragraphs under the header - Determining Proper Inflation Pressure.

Bottom line; never use inflation pressures below vehicle manufacturer recommendations.

https://www.ustires.org/sites/defaul...TruckTires.pdf

It appears that you are now agreeing that this is a tire industry recommendation? Is that correct?
If so, a simple YES would suffice. And we can put this thread to bed.

[Bill Gail]

Originally Posted by FastEagle

Attachment 277317

Good morning ,
FastEagle thank you , you've made my argument for me.

The sticker you show confirms my position.

That is , lighter loads should run at corresponding tire psi.

My statement that you responded to was, if tires weren't allowed to have psi adjusted for lighter weight due to regulations the sticker would state that the tires psi MAY NOT be adjusted for actual loads.

The sticker image in your response clearly shows lower psi for corresponding lighter load.

[LOG]

There is a tire expert with wide recognition in the RV world. His credentials and experience are substantial. He has a website RVTIRESAFETY.NET. On September 29, 2017 he wrote an article titled " Who to believe on tire inflation." It specifically addresses the question on Tire Placard and tire pressures that have been discussed in this thread. I highly recommend anyone interested in RV tire pressures to read this article.

[FastEagle]

Originally Posted by LOG

It appears that you are now agreeing that this is a tire industry recommendation? Is that correct?
If so, a simple YES would suffice. And we can put this thread to bed.

NO! It's the USTMA making it easier to understand.

When NHTSA says the correct tire inflation pressure is what has been recommended by the vehicle manufacturer, does it imply something less is OKAY?

[Bill Gail]

Originally Posted by FastEagle

NO! It's the USTMA making it easier to understand.

When NHTSA says the correct tire inflation pressure is what has been recommended by the vehicle manufacturer, does it imply something less is OKAY?

Yes , it does imply exactly that

As it doesn't disallow running the tires at the sidewall inflation psi , which normally is considerably greater than the door placard psi , It makes the inverse true. If the load is less than max weight a corresponding safe psi can be used.

Following is a direct quote from RVTIRESAFETY , which shows a beaurocracy running amok , wanting to tell us what to do , but not wanting to take responsibility for their direction.

" So the bottom line is that for most RVs the inflation is basically the level needed to support 100% to 110% of the GAWR.
But many RVs are not loaded to that level which means you can lower the inflation to achieve better ride as long as you don't end up with overloaded tires.
DOT doesn't trust the average driver to know the actual weight of the RV. They have done studies and discover that a significant portion of the population thinks they are OK but actually have tires in overload.
So the DOT doesn't publish alternative inflation guidelines and RV companies follow what the government does.
It's just that simple "

Legislating to the lowest common denominator.