Tire Pressure for Sailun S637T Tires

[scottkeen]

I have Sailun S637T ST235/80R16 G/14PR tires, which is the recommended tire size for my RV.

The sticker from Keystone says to fill the tires to 80 psi.

The maximum pressure these tires are rated are 110 psi.

The trailer service center sold me the Sailuns and installed them, and they do all my trailer inspections and service. They filled the Sailuns to 100 psi, which is what they recommended.

Who is correct? What pressure should I fill these tires to?

[mlh]

The higher the pressure the higher the load limit and the cooler tires run. There is no reason to run your tires at 80 pounds except they will ride a little smoother.
Just be sure you have 110 pound rims.
Lynwood

[scottkeen]

Originally Posted by mlh

The higher the pressure the higher the load limit and the cooler tires run. There is no reason to run your tires at 80 pounds except they will ride a little smoother.
Just be sure you have 110 pound rims.
Lynwood

Thanks for the reply.

Did you mean to say, "...no reason to run your tires at 100 pounds..."?

Keystone spec says 80 pounds.
My trailer service station said 100 pounds. They are the ones who sold and installed the tires.

I just want to know what is correct. I'm programming my TPMS and need to know what to enter for the normal pressure, and then inflate/deflate my tires to that number.

[Carl n Susan]

Your RV was originally equipped with Load Range E tires (per the sticker). The maximum pressure for them is 80 P.S.I.. Your G range Sailuns are capable of up to 120 P.S.I. As long as your rims are able to handle the increased pressure, the 100 P.S.I. is correct.

[TCmontana]

Carl you mentioned “if your rims can handle it”. How can you tell that about your rims?

[Hblick48]

If you have alloy wheels, the psi rating will bea number cast on the rear of the wheel, usually on a spoke. You may need to remove one to see. If your wheels are steel, you should have no problem. In either case, you should have metal valve stems.

My rig originally came with load range E, same as you. I have Transeagle all steel load range G on my rig. They are a Sailun knock off. I run tire pressure at 95, which is what you run load range F at.

[Carl n Susan]

Originally Posted by TCmontana

Carl you mentioned “if your rims can handle it”. How can you tell that about your rims?

Your 2020 3931FB has rims good to 110 P.S.I. and should have come with Sailuns already. But the max P.S.I. is stamped on the back side of the spoke on the wheels. You have to remove the wheel from the RV to see it.

[scottkeen]

Originally Posted by Hblick48

If you have alloy wheels, the psi rating will bea number cast on the rear of the wheel, usually on a spoke. You may need to remove one to see. If your wheels are steel, you should have no problem. In either case, you should have metal valve stems.

My rig originally came with load range E, same as you. I have Transeagle all steel load range G on my rig. They are a Sailun knock off. I run tire pressure at 95, which is what you run load range F at.

Is there a way to tell what these wheels are (7-spoke)? I'm guessing alloy. These came with the RV when I bought it from the RV dealership, I'm the 2nd owner.

(see photo. btw, those are the old tires before I replaced them with Sailuns)

If they cannot handle the 100 psi of the Sailuns, should I deflate the Sailuns to 80 PSI per the E-rated tires?

Which raises the question -- what is the threshold for the wheel not being able to handle the PSI of the tire? (i.e. if the correct pressure for the G-rated Sailun is 100 PSI, then should the wheel be rated to handle 10% over that pressure? 20%?)

[rohrmann]

Thise wheels are Sendel T02 wheels, and being 8 lug wheels, they are rated 110 psi. http://sendelwheel.com/wheels/t02.html
We have the Sendel T04 wheels, also rated 110 psi, and with our Sailuns, run them at 100-110 psi, and try to keep them closer to 110 psi most of the time.

[RMcNeal]

Scott, even if you set the cold pressure to 110 psi, you will see when using your TPMS that they will heat up going down the road to as much as 135 psi, perhaps more. The warmer the tire, the higher the pressure. It really shouldn't make much difference if you go 100 or 110 psi on the cold pressure since your rig was originally load range E at 80 psi. You really have more tire than you need for the load either way, assuming you haven't overloaded the weight of the trailer. The Mountaineer is the previous version of the current High Country trailers, so they are lighter weight than legacy Montana's. You most likely do not have 7,000 lb axles that would require the Sailun Load Range G tires anyway.

[JandC]

No matter what I would run any G rated tires at the higher psi, maybe not 110psi, but at least 100 psi. If you keep them closer to 80 or 85 psi you will get more sidewall flex and create more heat inside the tire. Running those lower pressures could be an issue if traveling in the summer out west.

[scottkeen]

Originally Posted by RMcNeal

...The Mountaineer is the previous version of the current High Country trailers, so they are lighter weight than legacy Montana's. You most likely do not have 7,000 lb axles that would require the Sailun Load Range G tires anyway.

The GVWR of my trailer is 14,320 lb
The GAWR (each axle) is 6,000 lb

How does the GVWR exceed the 2x GAWR?

This is the toy hauler model.

[Theunz]

Your kingpin is carrying the remainder of the weight which it transfers to your tow vehicle.

[CalandLinda]

Originally Posted by scottkeen

I have Sailun S637T ST235/80R16 G/14PR tires, which is the recommended tire size for my RV.

The sticker from Keystone says to fill the tires to 80 psi.

The maximum pressure these tires are rated are 110 psi.

The trailer service center sold me the Sailuns and installed them, and they do all my trailer inspections and service. They filled the Sailuns to 100 psi, which is what they recommended.

Who is correct? What pressure should I fill these tires to?

Because your LRG tires are the same designated size as the OE tires, you have the option to use inflation pressures form 80 PSI to 110 PSI.

Because the designated size goes all the way to LRG, the OE wheels and valve stems should be rated for the highest load range in that tires designated size. However, there is no regulation that directs the vehicle manufacturer to do that, so, like others have said, check your wheels and valve stems before inflation above 80 PSI.

NOTE: Load range is not part of a designated size such as ST235/80R16.

[prndl]

Tire pressure is a variable and is dependent on the weight of your individual trailer.

Get the Sailun Tire Pressure Load Range Chart in the Files section of this forum and download it for your records.

[CalandLinda]

Originally Posted by prndl

Tire pressure is a variable and is dependent on the weight of your individual trailer.

Get the Sailun Tire Pressure Load Range Chart in the Files section of this forum and download it for your records.

Nope! It's dependent on the trailers certified GAWRs. Those recommended cold inflation pressures on the certification label are the minimum for that vehicle with OE tires installed. Optional inflation pressures START at the minimum recommendation and END at the PSI value on the tire for maximum load capacity for that/those tire/tires.

[prndl]

Originally Posted by CalandLinda

Nope! It's dependent on the trailers certified GAWRs. Those recommended cold inflation pressures on the certification label are the minimum for that vehicle with OE tires installed. Optional inflation pressures START at the minimum recommendation and END at the PSI value on the tire for maximum load capacity for that/those tire/tires.

Do what you think is right.

[Eagleback]

Originally Posted by RMcNeal

The Mountaineer is the previous version of the current High Country trailers, so they are lighter weight than legacy Montana's. You most likely do not have 7,000 lb axles that would require the Sailun Load Range G tires anyway.

The Mountaineer at least 2014 is not the previous version of the high country as our mountaineer has hydraulic slides, not electric 7000 lbs axles and a 12 in beam not 10 as on the high country from my year. Our year had the models of bigsky, the montana, the mountaineer and then the high country. Just saying as the weights are different between the two.

[RMcNeal]

My apologies. I was told that the Mountaineer model became the High Country by our dealer. I don't think they make that model anymore, which made sense to me that it was basically a name change.

[mlh]

You can go by the weight rating for the tire or the trailer. That will get you by and it’s ok. Any thing between 80 and a 110 will work. Your trailer will ride a little rougher and your tires run a little cooler the higher the pressure. I prefer higher pressure it’s better for your tires because they run cooler and have more weight carrying capacity.
The best thing for you is to do a little research and find out for sure yourself.
Lynwood