Tire Pressure Questions

[cooney]

After a failure of one of the GY Marathon tires, we replaced them all. I should add that these were the original tires on our 2008 AS Safari 27' FB, which means they were on for almost 4 and a half years.
Anyway, we put on four new Gladiator tires, this time w/ an E rating, instead of the Goodyear D rating. The sidewall has a pressure rating of 80 psi, but the dealer (with whom I have some reservations as to experience) recommends that we carry only 55 psi, for reasons of the shape of the aluminum wheel. I asked if that would cause overheating of the tires, and he assured me it would not. This dealer, BTW, is in a small southwestern town, and we pretty much had to use him as our choices were limited.
Comments? Advice? We want safety, primarily, and of course reasonable tire longevity, as well.
Thank you all in advance...
All the Best...


JC

[HowieE]

The only way to determine the correct tire pressure is to weigh your trailer and refer to the tire inflation chart. This is the Goodyear chart.

http://www.goodyear.com/truck/pdf/da...dInflation.pdf

Since the Government requires all manufactures to meet the same standards for a give tire size you can use this chart for any manufacture.

You are correct in your distrust of the dealers recommendation as they just go by the "door sticker" and have little knowledge beyond that.



.

[MrUKToad]

I was advised to run my 65psi tyres at 55psi and that seems to have been good for us. We were doing lots of highway driving in some very hot Gulf Coast weather this summer and the trailer tyres were no hotter than the tow vehicle tyres, as far as my non-scientific measurement methods could tell, anyway. The advice I had came from a very knowledgeable towing professional so maybe you should speak with someone who can give you towing specific information.

[bryanl]

re: "The only way to determine the correct tire pressure is to weigh your trailer and refer to the tire inflation chart." -- this might be worthwhile for starts but, IMHO, this is not a good approach as it does not take into consideration individual circumstances and it contains numerous hidden assumptions.

The reason you inflate tires is to be able to handle the load at the speed you drive without causing excessive heating that occurs from tire flexing.

You do want tires and wheels properly rated for the load they carry for best performance. Overkill tends to be rather harsh so bigger isn't necessarily better, especially for trailers that can pop rivets and vibrate things out of place.

On TT tires, it is usually best to error a bit on the high side, though. That is why some recommend maintaining max sidewall PSI in the tires -- assuming that the tires are properly rated for the TT loading.

If you don't have one of those newfangled tire pressure monitoring systems - or even if you do - one of the best things you can do is to get an IR thermometer so you can do a walk-around at every stop to check tire and hub temperatures. Such activity is good for DVT prevention as well as being able to catch any tire or hub getting hotter than it should.

If your tires tend to run at over 120F, the odds are good that they are under-inflated. If they tend to run at near ambient temperatures, the odds are that they may be over-inflated. Any tire or hub that is quite different from the others in temperature needs to be investigated.

Keep in mind that hot tires need more air. In summer desert conditions, keep the speed down and tire pressure up to help keep the tires running cool. It is heat that is the major destroyer of tires.

[Al - K4GLU]

Well if you listen to Airstream they will always tell you to run the tires at the max PSI listed on the sidewall. I upgraded to the 16" Michelin's and they advise running these at 80 psi.

[HowieE]

Airstream customer service is not noted for it's technical knowledge and more often directed by Lawyers in the information they present.

The Department of Transportation has required a lot of research and product standards on this subject. You choise is to follow the conclusions form that research or go with the Lawyers.

[bryanl]

re: "The Department of Transportation has required a lot of research and product standards on this subject. You choise is to follow the conclusions form that research or go with the Lawyers." -- oh my, it is never pleasant when it gets in these sort of false dichotomies.

There are many good reasons for Airstream's advice and they are not alone. The DOT is not the only one doing research, either. It is also necessary when evaluating any research to properly qualify the findings as they might apply to your circumstances and requirements.

Roger Marble has been in the business a while and his blog RV Tire Safety has a lot of good information on this topic. Again, always be skeptical, look for a sound rationale, and don't single source.

What happens when a tire is under-inflated? what happens when it is over-inflated? What is used to determine if it is under or over? These things you need to know to be able to determine if it is indeed a conspiracy or a government bureaucracy that should drive your decisions - or maybe your own wits.

[dznf0g]

Originally Posted by bryanl

re: "The Department of Transportation has required a lot of research and product standards on this subject. You choise is to follow the conclusions form that research or go with the Lawyers." -- oh my, it is never pleasant when it gets in these sort of false dichotomies.

There are many good reasons for Airstream's advice and they are not alone. The DOT is not the only one doing research, either. It is also necessary when evaluating any research to properly qualify the findings as they might apply to your circumstances and requirements.

Roger Marble has been in the business a while and his blog RV Tire Safety has a lot of good information on this topic. Again, always be skeptical, look for a sound rationale, and don't single source.

What happens when a tire is under-inflated? what happens when it is over-inflated? What is used to determine if it is under or over? These things you need to know to be able to determine if it is indeed a conspiracy or a government bureaucracy that should drive your decisions - or maybe your own wits.

WHAT!!!! Rely on ourselves????? How last century and out of date. Oh, wait......it worked.......now I understand most of our problems!

[richinny]

what is the max psi rating of the wheels and valves?

Originally Posted by cooney

After a failure of one of the GY Marathon tires, we replaced them all. I should add that these were the original tires on our 2008 AS Safari 27' FB, which means they were on for almost 4 and a half years.
Anyway, we put on four new Gladiator tires, this time w/ an E rating, instead of the Goodyear D rating. The sidewall has a pressure rating of 80 psi, but the dealer (with whom I have some reservations as to experience) recommends that we carry only 55 psi, for reasons of the shape of the aluminum wheel. I asked if that would cause overheating of the tires, and he assured me it would not. This dealer, BTW, is in a small southwestern town, and we pretty much had to use him as our choices were limited.
Comments? Advice? We want safety, primarily, and of course reasonable tire longevity, as well.
Thank you all in advance...
All the Best...


JC

[withidl]

I keep my ASCL 31’ tires inflated to the maximum sidewall pressure (65 psi) so that if a tire does loose pressure the load on the remaining tires can be better supported at speed if I am not aware of the pressure loss; or if I become aware of the pressure loss and remove the tire I will be able to limp to a repair facility on the remaining tires

I know of what I speak as I had it happen to me several years ago when one of my aluminum wheels failed due to a hairline longitudinal crack just inside where the spokes attach to the rim. This happened at some point between Atoka, Oklahoma, where I got fuel and Tulsa, Oklahoma, my destination, where I became aware of the pressure loss. The tire on the failed wheel “seemed” OK, as it did not evidence any damage. I put the spare on and eventually made my way to Jackson Center where they replaced the wheel at no cost even though I was not in warranty (the tire on the failed wheel became my spare).