new tires

[Ozark Kayaker]

I have a Rockwood 8314bss and just ordered a new set of tires, Goodyear Marathon St225r7515. They require 65psi, the std tires take 50psi. Will the wheels handle the higher psi? If so, should i have them install metal valve stems?

[KingFisher]

I had new tires put on my windjammer, went from c range to e range. I told the tire store d range but they ordered e range instead, price difference was negligible so I was ok with it. 50 pounds psi to 80 pounds psi. The max psi is supposed to be on the rim somewhere, I couldn't find it.

I emailed hispec who is the manufacturer of the aluminum wheels for guidance. They still haven't returned my email, they could care less.

Tire shop said it would be ok and they put in metal valve stems for me.

[Mtelkman]

I have load range e tires on my 5 lug rims as well. Tire shop added metal stems and told me the wheels would handle the 80psi pressure fine. I trust them to know their tire stuff.


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[Tireman9]

Originally Posted by Ozark Kayaker

I have a Rockwood 8314bss and just ordered a new set of tires, Goodyear Marathon St225r7515. They require 65psi, the std tires take 50psi. Will the wheels handle the higher psi? If so, should i have them install metal valve stems?

Whenever replacing tires you should also replace the valves as there are rubber parts in valves that age just as the rubber in tires age.

Standard (low cost) rubber stems have 65 psi MAX rating. Metal bolt in stems which can be had from Amazon at $8 a set of four so don't let the dealer charge you too much. Metal stems are also preferred for TPMS use.

[Klbrown53]

We have same unit and after first year I replaced tires with Maxxis D load rating which call for 65 psi. I also asked Discount Tire about extra pressure on wheels and they said no problem. But I do not know about 80 psi. I make sure and keep cold pressure at 60 or above. Had them replace stems with metal also. Funny thing happened when we got the cheap tires and rubber stems off. I no longer have to air them up every time I take it out and every two or three days when we are camping. Marathons were on my previous trailer and we had no trouble with them. Anything is better than the factory tires. I will never pull another RV off of a sales lot without tires that I trust on it. It just is not worth the worry I experienced that first year.


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[Tireman9]

Originally Posted by Klbrown53

We have same unit and after first year I replaced tires with Maxxis D load rating which call for 65 psi. I also asked Discount Tire about extra pressure on wheels and they said no problem. But I do not know about 80 psi. I make sure and keep cold pressure at 60 or above. Had them replace stems with metal also. Funny thing happened when we got the cheap tires and rubber stems off. I no longer have to air them up every time I take it out and every two or three days when we are camping. Marathons were on my previous trailer and we had no trouble with them. Anything is better than the factory tires. I will never pull another RV off of a sales lot without tires that I trust on it. It just is not worth the worry I experienced that first year.


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Not sure why you went with LR-E but are not even running 65 psi which would be correct for LR-D.
It is the air pressure that carries the load not the tire. Also due to the suspension design, multi axle trailers place shear force loads that run 24% higher that the forces experienced on the TV.

If you Google "Interply Shear" or "Interply Shear tires"you can learn more. If you aren't comfortable with the Techno-Babble then here is what you should do when pulling a multi axle TT to get the longest life from the tires.

Inflate the TT tires to their sidewall max, which for LR-E tires is 80 psi. In addition to reducing the shear force that is trying to tear the belts& tread off the body of the tire in each and every turn you will have much improved "Reserve Load". HERE is a link to a few posts that mention "Reserve Load"

[Klbrown53]

Tire man,

I did not go with E rated tires. That was Kingfisher that posted and as I recall because of what the supplier sent them. The original poster was asking if his factory wheels would support the 65psi of D rated tires. Mine are D rated and as I said I run 60psi plus cold. In other words, I never let them get below 60.


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