Tire PSI on higher load rated tires?

timelinex

Advanced Member
Joined
Mar 28, 2022
Messages
89
I replaced my OEM Westlake 235/80/R16's with Carlisle CSL16 235/85R16's on my 2021 381m.

My old tires had a maximum load rating of 4,080lb at 110psi and the new ones 4,400lb at 110psi.

I would think that I should lower the cold psi to match load ratings; otherwise, I will have an overinflated wear pattern and an unnecessarily stiffer ride.

I called Grand Design with a different question, but ended up asking the tech on the phone about whether I should stick to the PSI on the trailer's sticker or match load ratings. He said the sticker applies if you have OEM tires, otherwise he agrees it would be a good idea to match load ratings.

Unfortunately, Carlisle does not put out a chart for load rating by PSI, and when I contacted them, they said they only test and recommend max psi on their tires. I did find load ratings by psi for other tires in the same class, which all seem to match with each other so I think it is probably a pretty standardized thing. For example here is one for Sailun tires:

https://fifthwheelst.com/documents/Copy of Load and Inflation All ST-Modified.pdf

It shows that for me to match my old tires load rating I should be at 100 psi.

Is there any reason not to lower my psi to 105? I don't actually care about the wear pattern since I will likely age out of tires before wearing them out. Here are my main reasons:

1. It can get to 120 degrees here and the tires can occasionally get super hot on the sun's side (I've seen 130+). Lower PSI can keep the hot temps below 130 (which is what they are rated to).

2. On longer trips, because of temperature and pressure swings, it can get annoying to fill and drain 6 tires every night/morning. If I set it at 105, I have a bigger buffer, where 110 is still fine, and maybe something like 102 is still fine as well.

What do you guys think?

EDIT: For reference, I don't even run my trailer at max weight anyways. I'm usually around 19k out of 20k.
 
Last edited:
FWIW, I ran my "G" rated Sailun tires on our old trailer at 90-100 psi, with about 2500 lbs./tire and did that for about 6 years, with no issues, and the tires still looked good. And I didn't adjusted the pressure unless the pressure was below what I had set as the max pre-travel pressure. And NEVER lowered the pressure.

What weight do you actually have on your tires?
 
I replaced my OEM Westlake 235/80/R16's with Carlisle CSL16 235/85R16's on my 2021 381m.

My old tires had a maximum load rating of 4,080lb at 110psi and the new ones 4,400lb at 110psi.

I would think that I should lower the cold psi to match load ratings; otherwise, I will have an overinflated wear pattern and an unnecessarily stiffer ride.

I called Grand Design with a different question, but ended up asking the tech on the phone about whether I should stick to the PSI on the trailer's sticker or match load ratings. He said the sticker applies if you have OEM tires, otherwise he agrees it would be a good idea to match load ratings.

Unfortunately, Carlisle does not put out a chart for load rating by PSI, and when I contacted them, they said they only test and recommend max psi on their tires. I did find load ratings by psi for other tires in the same class, which all seem to match with each other so I think it is probably a pretty standardized thing. For example here is one for Sailun tires:

https://fifthwheelst.com/documents/Copy of Load and Inflation All ST-Modified.pdf

It shows that for me to match my old tires load rating I should be at 100 psi.

Is there any reason not to lower my psi to 105? I don't actually care about the wear pattern since I will likely age out of tires before wearing them out. Here are my main reasons:

1. It can get to 120 degrees here and the tires can occasionally get super hot on the sun's side (I've seen 130+). Lower PSI can keep the hot temps below 130 (which is what they are rated to).

2. On longer trips, because of temperature and pressure swings, it can get annoying to fill and drain 6 tires every night/morning. If I set it at 105, I have a bigger buffer, where 110 is still fine, and maybe something like 102 is still fine as well.

What do you guys think?

EDIT: For reference, I don't even run my trailer at max weight anyways. I'm usually around 19k out of 20k.

I did the same thing as you, except I DID go with the Sailuns (235/85R16) and they too are 4400 lbs load capacity at 110 psi. I used Sailun's chart and I decided on the 100 psi number, as that exactly equal what the original Westlake "G" 235/80R16 tire was. Those tires did not show any kind of abnormal wear pattern and were almost 5 years old and probably closing in on 20K miles. I replaced them because they were starting to weather crack on the sidewall area of a couple of the tires.

Oh, and the reason I bought the 235/85R16 Sailuns.....they were less expensive than the 235/80R16 Sailuns....weird huh!
 
"Oh, and the reason I bought the 235/85R16 Sailuns.....they were less expensive than the 235/80R16 Sailuns....weird huh!"

That's the same reason I bought that size.
 
"Oh, and the reason I bought the 235/85R16 Sailuns.....they were less expensive than the 235/80R16 Sailuns....weird huh!"

That's the same reason I bought that size.

That adds up for sure, especially when buying 6 tires, mounting/balancing/etc.
 

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