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Old 04-14-2021, 01:12 PM   #21
scottkeen
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I called my local trailer service center, "Trailer Care" in Hamilton, VA who sold and installed these tires 2 years ago and asked what PSI the head trailer mechanic says I should fill these tires to (they do all the service on my RV).

She went and checked with him and came back, "He said 100 PSI".

I checked my tires last weekend and they were 90-95 PSI so I topped them up to 105 PSI on my Viair inflator gauge, and my TST-507 TPMS read the tires as 98-99 PSI. Close enough to 100 PSI.
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Old 04-18-2021, 03:31 PM   #22
Bill M
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As previous posts have said, if rims rated at 110 psi then tires should be 110 cold psi. If you run less than that, then max speed is reduced. 110 = max 75 mph, 80 = 65 mph. An undeflated cold pressure tire will create more heat/pressure. Tire manufacturers print these pressures for a reason unless you are a rocket scientist don't change them.
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Old 04-18-2021, 03:39 PM   #23
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And don't forget when talking Sailun 637s and tire pressure you need to specify what size you have. I have Sailun 637s in a 17.5" H Rated which run at 125 PSI.
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Old 04-18-2021, 04:48 PM   #24
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The data on the sticker you showed is for the OEM load range E tire. Since you have upgraded to LR G, if you rims are rated for 110 psi, you can run 110 psi in the Sailun tires. To check the rims pull one wheel and look on the inside of the spokes to see if 110 psi is shown. If not, only trust the rims for 80 psi and consider replacing them with 110 psi rims so that you can take full advantage of the extra load carrying capacity of the LR G tires. Yes, your coach will ride a little harder with tires at 110 vs. 80. It has not been a problem for us with the G614s.
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Old 04-18-2021, 08:38 PM   #25
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Originally Posted by laverdur View Post
The data on the sticker you showed is for the OEM load range E tire. Since you have upgraded to LR G, if you rims are rated for 110 psi, you can run 110 psi in the Sailun tires. To check the rims pull one wheel and look on the inside of the spokes to see if 110 psi is shown. If not, only trust the rims for 80 psi and consider replacing them with 110 psi rims so that you can take full advantage of the extra load carrying capacity of the LR G tires. Yes, your coach will ride a little harder with tires at 110 vs. 80. It has not been a problem for us with the G614s.
I'm not a speed demon with the RV, I keep it at 55 mph. Even with tire psi at 95-100 on these Sailuns, it's just my comfort level to keep it around 55 mph. Maybe that will change over time, the more I tow the RV.
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Old 04-18-2021, 09:08 PM   #26
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I agree. When towing, speed is not what's important. On roads posted at 65 mph or higher I run 65. I know my G614s are rated for higher speed but that fails to take into account fuel economy and safety.
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Old 04-18-2021, 09:13 PM   #27
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Originally Posted by laverdur View Post
I agree. When towing, speed is not what's important. On roads posted at 65 mph or higher I run 65. I know my G614s are rated for higher speed but that fails to take into account fuel economy and safety.
...now when I roll the motorcycle out of the toy hauler and take it for a ride, then 55 mph is something I remember briefly seeing in 2nd gear!
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Old 04-18-2021, 10:52 PM   #28
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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.
Wow...are those numbers based on actual observation on your rig?
I have NEVER seen pressure increases of that magnitude and I have driven in some really hot climates. Most increase I've seen is closer to 10-12 lbs.
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Old 04-19-2021, 08:25 AM   #29
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Originally Posted by Bill M View Post
As previous posts have said, if rims rated at 110 psi then tires should be 110 cold psi. If you run less than that, then max speed is reduced. 110 = max 75 mph, 80 = 65 mph. An undeflated cold pressure tire will create more heat/pressure. Tire manufacturers print these pressures for a reason unless you are a rocket scientist don't change them.
Please provide a USTMA or FMVSS reference??????
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Old 04-19-2021, 09:01 AM   #30
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The tire pressure load tables are designed for the optimum tire pressure so that the tire has most surface area on the ground, not over inflated not under inflated.

So I don't recommend the max pressure, especially since you have g rated tires.
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Old 04-19-2021, 04:30 PM   #31
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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.
Carl n Susan, FYI, you do not need to remove your wheel to see the wheel rating. Just crawl under the rig and look at the spokes. Mine are stamped 110 on every spoke. Easy to see. Wheels are OEM.
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Old 04-19-2021, 04:45 PM   #32
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[QUOTE]I run my Sailuns at 105. If I m loaded heavy (but not over) which rarely happens, I’ll go to 109 psi. My trailer shop says tires will ride cooler and roll smoother when close to fully inflated. I get a full footprint at 105 psi, then the shop proceeded to show me as they backed it out of the shop. I set my tpms based on 105 psi.cold inflation.
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Old 04-19-2021, 04:59 PM   #33
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Carl n Susan, FYI, you do not need to remove your wheel to see the wheel rating. Just crawl under the rig and look at the spokes. Mine are stamped 110 on every spoke. Easy to see. Wheels are OEM.
I did say you *MAY* have to remove the wheel... Not all wheels are like yours (it would help if you listed your year and model in your signature). My T04 wheels have the P.S.I. rating on only one spoke in small numbers. Impossible to see unless that spoke is at 6:00 o'clock.
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Old 04-19-2021, 05:01 PM   #34
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Montana changed their tires from E rated to F rated as the E rated tires were barely able to carry the load, and they had blow out issues. . My OEM tires were E rated. Keystone said I should switch to at least an F rated tire, and G rated was more than enough. I would not run the Sailun G rated at 80 psi. Up to you though.
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Old 04-20-2021, 08:00 AM   #35
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(snip) I would not run the Sailun G rated at 80 psi. Up to you though.
I checked the pressure on my Sailun G rated tires, they are at 98-99 psi.

Is there a danger of running the Sailun G rated tires at 80 psi? Not that I'm gonna do that, but just wondering why you wouldn't.
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Old 04-20-2021, 08:08 AM   #36
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FWIW, I have my TST 507 TPMS alerts for the trailer set to:

Low Pressure alert = 90 psi (10% below 100 psi)
High Pressure alert = 125 psi (25% above 100 psi)

The 10% low and 25% high alert thresholds is what the TST 507 user manual recommends.

---
Sidebar: The TST 507 TPMS alerts for my 2007.5 Dodge Ram 3500 DRW truck are set to:

Front
Low Pressure alert = 58 psi (10% below 65 psi)
High Pressure alert = 81 psi (25% above 65 psi)

Rear dually
Low Pressure alert = 54 psi (10% below 60 psi)
High Pressure alert = 75 psi (25% above 60 psi)

I didn't know what pressure to fill my rear tires to, the sticker on the inside of the door says "Front = 65 psi, Rear = 40 psi normal load, 65 psi max load" so I figured 60 psi for the rear was some compromise between 40-65. What do you have your rear truck tires filled to?
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Old 04-20-2021, 08:44 AM   #37
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They are intended for heavier loads and higher pressure, which is why most folks run them around 105 to110 psi. I run mine at 107 and keep them there. They have a very heavy side wall and a low pressure (80 psi) causes more side wall flex which causes more heat. Also more stress and flex on sidewall when turning, especially in tight turns. If you run them at a higher pressure they will stay cooler, roll easier, should give you better mileage, and less wear on edges. Unless you put lots of miles on them, they will age out before they wear out.
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Old 04-20-2021, 09:36 AM   #38
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Quote:
Originally Posted by scottkeen View Post
FWIW, I have my TST 507 TPMS alerts for the trailer set to:

Low Pressure alert = 90 psi (10% below 100 psi)
High Pressure alert = 125 psi (25% above 100 psi)

The 10% low and 25% high alert thresholds is what the TST 507 user manual recommends.

---
Sidebar: The TST 507 TPMS alerts for my 2007.5 Dodge Ram 3500 DRW truck are set to:

Front
Low Pressure alert = 58 psi (10% below 65 psi)
High Pressure alert = 81 psi (25% above 65 psi)

Rear dually
Low Pressure alert = 54 psi (10% below 60 psi)
High Pressure alert = 75 psi (25% above 60 psi)

I didn't know what pressure to fill my rear tires to, the sticker on the inside of the door says "Front = 65 psi, Rear = 40 psi normal load, 65 psi max load" so I figured 60 psi for the rear was some compromise between 40-65. What do you have your rear truck tires filled to?
Most of the guys with duallys that I know that tow heavy are running lower pressures in the rear duals when not towing (between 40-50 psi.) Depends on the tires of course...usually the stock tires are E rated with 80 psi max cold pressure. Nobody I know runs them that high. I run 65 fronts and 45-50 rear, bump it up to 65 when towing. But I'm also running non stock tires, although still rated at 3,195 lbs @ 80 psi according to the sidewall info.
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