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JIMNLIN

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Posted: 02/08/20 07:01pm Link  |  Quote  |  Print  |  Notify Moderator

Most folks understand ply sheer stress with tires on trailer with close spaced axles.
And most folks can read all the website info on why max sidewall pressures work best for tires on a trailer.

And most folks understand those load pressure charts are a minimum pressure for that load only with no reserve that hi scrub tires on a trailer needs unlike low scrub tires on the tow vehicle.

For those that don't understand the need and reasons for higher pressures on any tire on a trailer should spend some time on Tireman9 rvtiresafety.net website. You get input from a actual tire engineer who understands why max pressures are recommended. Its suggested reading for those interested in knowing the howz and whyz. http://www.rvtiresafety.net/2019/07/why-inflate-motorhome-tires-differently.html
This clicky is one on several Tireman9 has on the subject on pressures for tires on a trailer. Lots of reading.

* This post was edited 02/08/20 07:12pm by JIMNLIN *


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cummins2014

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Posted: 02/09/20 10:19am Link  |  Quote  |  Print  |  Notify Moderator

Cummins12V98 wrote:

Curly2001 wrote:

The Endurance tires I purchased from Discount came with the advice from Discount to run them at MAX pressure all the time for the best towing/tire results. The trailer came with China bombs which did blow up, I tried Carlisle which one blew apart, and now have Endurance which so far, have done fine in the Arizona heat. Last year came through Phoenix at 112 degrees with my fingers crossed, checking my tire monitors and did make it to Tucson with no problems.
Curly


That is purely a CYA statement on their part. Example, some may be right on the edge of having enough capacity on a 65psi "D" rated tire. It would be stupid to run 80psi stepping up to "E" If the tires weight dictates 65. GY Tech will tell you to use the weight/inflation chart when up sizing load range and add 5psi to what the chart says.

Example would need 70psi. Per GY Tech running too much air will give you less stopping, rougher ride and more tire wear.

To the nay sayers that I am sure will comment WHY do every tire made have a load/inflation chart if it should not be used?



My fifth wheel is a Montana 38 foot long, its GVWR 15,500, on 7K axles. IF that fifth wheel is loaded to its max GVWR ,and I will be conservative here ,and only use 20% for the pin, giving it more weight on the axles, when quite possibly it could more then the 20%.

20% of 15,500 is 3100 lbs leaving 12,400 on the axles or 3100 per tire . I am running Sailun S637's ST 235/85/16 rated for 4400 lbs at 110 psi. Inflation chart calls for , and I would be in the middle here 60 psi for 3060 lbs ,and 65 psi for 3200 . So according to YOU, and that inflation chart, I should be inflating those G rated tires at about 70 psi.

My point ,and I am curious ,there a lot of Montana fifth wheels out there running those Sailuns, I am going by just the number of posts on the Montana forum, I'm saying the ones that did not come with them. They come now with the G rated tires. . Anyone here on this forum running those Sailuns , lets say between 70-80 psi. with a fifth wheel in the neighborhood of 15-17K GVWR , that puts them around that 70-80 psi on the inflation chart. The heaviest Montana fifth out there as far as I can tell has a 16,500 GVWR.

I don't ,and won't run my G rated Sailun tires according to their inflation chart, and its very doubtful you will find anyone running those big Montana fifth wheels anywhere near 70-80 psi, they are most likely running at the least 95 or more. You seem to be the only one that I have heard push this inflation chart .

cummins2014

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Posted: 02/09/20 10:29am Link  |  Quote  |  Print  |  Notify Moderator

JIMNLIN wrote:

Most folks understand ply sheer stress with tires on trailer with close spaced axles.
And most folks can read all the website info on why max sidewall pressures work best for tires on a trailer.

And most folks understand those load pressure charts are a minimum pressure for that load only with no reserve that hi scrub tires on a trailer needs unlike low scrub tires on the tow vehicle.

For those that don't understand the need and reasons for higher pressures on any tire on a trailer should spend some time on Tireman9 rvtiresafety.net website. You get input from a actual tire engineer who understands why max pressures are recommended. Its suggested reading for those interested in knowing the howz and whyz. http://www.rvtiresafety.net/2019/07/why-inflate-motorhome-tires-differently.html
This clicky is one on several Tireman9 has on the subject on pressures for tires on a trailer. Lots of reading.



Even with all that you are saying, and I agree, it just doesn't make sense to follow these inflation charts on the bigger heavier fifth wheels, and I doubt there are any that do, other then the one individual. I don't run 110 on mine ,but I don't run 70 either . I know many in my weight range run around 100 on the Sailun G rated . And many that run the 110 .

Cummins12V98

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Posted: 02/09/20 03:58pm Link  |  Quote  |  Print  |  Notify Moderator

"So according to YOU, and that inflation chart, I should be inflating those G rated tires at about 70 psi."

YEP, Add 5 psi to the chart.

No I am not the only person doing so.

My Avion had GY "E" tires inflated to 80psi. Changed toy to GY "G" because there were no acceptable US Made "E" tires at that time so I went to the GY "G" tires and the chart said 80 so i ran them at 85psi. Ran this for several years and thousands of miles with perfect tread wear and NEVER hot.

Charts are there for a reason.


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Posted: 02/09/20 07:23pm Link  |  Quote  |  Print  |  Notify Moderator

I was surprised to see in this thread that Bridgestone has discontinued the R250. I have 6 of those on my TH. They've aged out. Thinking of replacing them with Sailun S637. What's the best place to by them? I'm in Florida.

cummins2014

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Posted: 02/09/20 08:56pm Link  |  Quote  |  Print  |  Notify Moderator

joebedford wrote:

I was surprised to see in this thread that Bridgestone has discontinued the R250. I have 6 of those on my TH. They've aged out. Thinking of replacing them with Sailun S637. What's the best place to by them? I'm in Florida.


If you have Big O tire shops , or online at Simple tire

cummins2014

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Posted: 02/09/20 08:57pm Link  |  Quote  |  Print  |  Notify Moderator

Cummins12V98 wrote:

"So according to YOU, and that inflation chart, I should be inflating those G rated tires at about 70 psi."

YEP, Add 5 psi to the chart.

No I am not the only person doing so.

My Avion had GY "E" tires inflated to 80psi. Changed toy to GY "G" because there were no acceptable US Made "E" tires at that time so I went to the GY "G" tires and the chart said 80 so i ran them at 85psi. Ran this for several years and thousands of miles with perfect tread wear and NEVER hot.

Charts are there for a reason.


It just seems you are the only one promoting it, but if you say so.

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Posted: 02/09/20 09:31pm Link  |  Quote  |  Print  |  Notify Moderator

joebedford wrote:

I was surprised to see in this thread that Bridgestone has discontinued the R250. I have 6 of those on my TH. They've aged out. Thinking of replacing them with Sailun S637. What's the best place to by them? I'm in Florida.


Walmart.com, free shipping to your house.


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CALandLIN

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Posted: 02/10/20 04:54am Link  |  Quote  |  Print  |  Notify Moderator

cummins2014 wrote:

Cummins12V98 wrote:

"So according to YOU, and that inflation chart, I should be inflating those G rated tires at about 70 psi."

YEP, Add 5 psi to the chart.

No I am not the only person doing so.

My Avion had GY "E" tires inflated to 80psi. Changed toy to GY "G" because there were no acceptable US Made "E" tires at that time so I went to the GY "G" tires and the chart said 80 so i ran them at 85psi. Ran this for several years and thousands of miles with perfect tread wear and NEVER hot.

Charts are there for a reason.


It just seems you are the only one promoting it, but if you say so.


Read any replacement tire SOP and they all follow the industry standard that says; the replacement tires MUST, provide a load capacity equal to or greater than, what the OE tires provided at vehicle manufacturer recommended cold inflation pressures.

JIMNLIN

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Posted: 02/10/20 07:32am Link  |  Quote  |  Print  |  Notify Moderator

joebedford wrote:

I was surprised to see in this thread that Bridgestone has discontinued the R250. I have 6 of those on my TH. They've aged out. Thinking of replacing them with Sailun S637. What's the best place to by them? I'm in Florida.

Bridgestone did discontinue the R250 but came out with a better updated 16" R238. Same commercial grade all steel ply carcass with the same tread type except the R238 has a bit more siping for a bit more wet traction.
With 15/32 of tread depth their popular with haulers who run them for 50k-70k miles on their service trailers. In that type or work we can wear out two sets a years vs maybs 4 sets of a 16" ST E tire with their 9 or 10/32 of tread depth.

JMO its been my experience the 16" Sailun S637 G load range at 4080-4400 lbs work best on 7k and 8k axles.....or overloaded 6k axles. These are the holy grail for commercial haulers who use 16" and 17.5" tires on our trailers. I have six 16" load G Sailuns on a triaxle GN stock trailer.
But I sure wouldn't run them or any tire on a trailer at 30+ percent under max sidewall.

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