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Old 02-19-2023, 06:39 PM   #21
rhagfo
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Quote:
Originally Posted by Rving life View Post
2235# is off the tire for dually rating. Bridge Duravis 500 tires
235/80/17 tire on Ram.
I was able to locate load rating table on tire for different psi levels.
They are load range 120, same as our Michelins are you sure dual rating isn’t 2,835? What is the single rating?
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Old 02-19-2023, 08:15 PM   #22
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Quote:
Originally Posted by Dacheedah View Post
No benefit to running a tire under rated pressure.
At 80psi, a 265/75R16 10ply itire will carry 3,085 pounds of load.
At 60 psi on a 10ply tire, the tire's load carrying capacity is reduced to 2,314 pounds per tire. from https://www.yournexttire.com/trailer...flation-chart/
Quote:
Originally Posted by chuckster57 View Post
I haul my fiver with the max pressure for the highest load rating. Had a rear inner tire go BOOM in Missouri with the old fiver hooked on. Was able to ease off the road and change to the spare. if I was at a lower pressure/load rating it might not have turned out the same. JMHO YMMV
Well in my case without 5er attached my rear axle on our 2016 Ram DRW weighs 4,400# add the 2,800# pin comes to 7,200#. Now if I run my rear tires at 80 psi they can carry 2,835# ea. or a total of 11,340# of capacity, on an axle rated for 9,750# so over 4,000# of excess capacity.
Well that now creates an issue of being overinflated for load carried, which will result in poorer traction both for accelerating and breaking.
I run my tires at 55 psi, towing giving me a capacity of 7,797#. This gives me good ride, good traction and good wear.



Your tires your choice, just my thoughts.

I still want to know how the OP's tires are only rated at 2,235# at 80 psi in dual configuration.
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Old 02-20-2023, 01:52 AM   #23
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Quote:
Originally Posted by Rving life View Post
2235# is off the tire for dually rating. Bridge Duravis 500 tires
235/80/17 tire on Ram.
I was able to locate load rating table on tire for different psi levels.
Is the 2235 lbs maxload right?
Loadindex 110 is 2335lbs, and nowadays almost always maxload belonging to loadindex.
2235lbs is between 108 and 109 loadindex.
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Old 02-20-2023, 05:12 AM   #24
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Reading the whole topic, I now see the questionmarks about the maxload you gave.

So topicstarter, give the right data.
Could not find this size in P-tire or Eur equivalent, wich then 2335lbs maxload would be possible .

If you give the right data, I will make a pressure/loadcapacity list for it, with a better formula (close to lineair calc) calculated, and reserve build in, and per axle given. Then you " ONLY" have to detetmine the axleloads acurately, and look them back in my made list.
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Old 02-23-2023, 11:38 AM   #25
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Tire info missing

I have decided to not add to the confusion but to use this thread as an example of how NOT to get the correct info on tire loading & inflation.


If you have a question on inflation the following information is REQUIRED or the answers are just guesses.


1. Complete tire designation. This includes the all the letters before and after the "size" numbers. The letter before tells us the "type" tire and normal application (P, LT, ST) Numbers and letters after the "size" numbers (C, D, E, G etc tells us the Load Range (Ply Rating) and the 3 digit numbers such as 123/135 give us the Load Index.



2.I don't care about the "Speed Symbol" as that only tells you how that tire, when brand new, performed on a 10 minute test at about 80% load. No tire in RV application should ever be run faster than 75 with 65 being a much better and safer max operating speed.


3. Actual scale measured load on your tires. Truck scales only give axle loads and almost no RVs have a 50/50 load split on the axle ends. Most are closer to 52/48% but some RVs have been found with over 1,000# more load on one end than the other. The only way to get the avtual tire loading is with individual tire readings on a scale. This isn't as easy to get as the axle reading so untill you get the individual weights I suggest you assume one end of each axle of the RV is supporting 52 or 53% or the axle load.


4. You need to remember that the load capacities shown in tables and charts are the MINIMUM COLD INFLATION required to support the load. There is NO "SAFETY FACTOR" or "SAFETY MARGIN" built into the tables. Tire Engineers will suggest you run at least +10% margin by increasing the cold inflation. Or you can run at the limit. Just as you would run at the engine Rev Limit all the time.
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Old 02-23-2023, 12:45 PM   #26
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New to the forum so I thought I’d jump in on this discussion with (hopefully) some good information to help focus the responses down to the correct tire.

Based on the OP’s info:

Quote:
Originally Posted by Rving life View Post
2235# is off the tire for dually rating. Bridge Duravis 500 tires
235/80/17 tire on Ram.
Bridgestone Duravis R500 HD tires are commercial-grade Light Truck (LT) radial ply tires. The correct size designation would be LT235/80R17. These are Load Range= E which denotes “equivalent” 10-ply (but does not necessarily mean it has 10 physical plies) and a max air pressure of 80psi. If we knew the Load Index, we would know the load capacity, but that has not been provided.

However, we do know the exact tire and size. So, going to the Bridgestone data book, using the above tire and size, we can see that this has a Service Description of 120/117R. Using our secret decoder ring, we see that for single tire, the Load Index is 120 = 3085lbs@80psi and for duals the Load Index is 117 = 2835lbs@80psi. And a speed rating of R = up to ~106mph.

I believe the 2235# rating mentioned in the quote above is incorrect. For a dual application, it should be 2835#. OP could you recheck that number on the sidewall and verify?

Source for all of this info: Bridgestone 2022 Commercial Tire Data Book

If you are going to run lower than max pressure (which I do support), be sure to weigh each tire for actual weights, make sure you use the correct pressure chart, add in your own safety margin, and check the pressures before each tow. BTW, the OEM tire pressure chart for this exact tire is listed in the above document on page 98.

+1 on all of Tireman9’s comments so not much else to add.

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Old 02-23-2023, 02:01 PM   #27
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I stand corrected the rating is 2835

Select Bridgestone Duravis R500 HD tire size for its maximum tire inflation and load capacity

LT235/80R17/E 120/117 tire with load range E and load index of 120 has a maximum single tire load capacity of 3085 lbs @ 80 psi, capable of supporting up to 3085 pounds or 1399 kilograms, while dual tire application with load index of 117 has a maximum dual tire load capacity of 2835 lbs @ 80 psi, capable of supporting up to 2835 pounds or 1286 kilograms when inflated to its maximum air pressure of 80 pounds per square inch (psi) or 552 kilopascals (kPa).
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Old 02-23-2023, 02:55 PM   #28
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Quote:
Originally Posted by Rving life View Post
I stand corrected the rating is 2835

Select Bridgestone Duravis R500 HD tire size for its maximum tire inflation and load capacity

LT235/80R17/E 120/117 tire with load range E and load index of 120 has a maximum single tire load capacity of 3085 lbs @ 80 psi, capable of supporting up to 3085 pounds or 1399 kilograms, while dual tire application with load index of 117 has a maximum dual tire load capacity of 2835 lbs @ 80 psi, capable of supporting up to 2835 pounds or 1286 kilograms when inflated to its maximum air pressure of 80 pounds per square inch (psi) or 552 kilopascals (kPa).
The correct maximum load capacity for that tire is 3042# at 80 PSI.
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Old 02-23-2023, 03:00 PM   #29
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Then the miswriting was 2235 instead of 2835lbs.

But now I can make a pressure/axleload list for you, in wich you "ONLY" have to search back the acurately determined axleloads for the situation.
Reserves all included, so dont do that yourselfes.

Gives 90% of calculated axleloadcapacity for 160kmph/99mph. I determined this to give maximum reserve, with still acceptable comfort and gripp.

Its always better to weigh per axle-end, then I would make a axle-end list with 95% used of calculated axle-end load. Then you search back the heavyest side on the axle,



Singleaxle/cold psi/ dualloadaxle
1717 lbs/ 22 psi / 3153 lbs/ EUR minimum
1855 lbs/ 24 psi / 3405 lbs
1991 lbs/ 26 psi / 3656 lbs/ US minimum
2127 lbs/ 28 psi / 3906 lbs
2263 lbs/ 30 psi / 4155 lbs
2398 lbs/ 32 psi / 4404 lbs
2533 lbs/ 34 psi / 4651 lbs
2667 lbs/ 36 psi / 4898 lbs
2801 lbs/ 38 psi / 5144 lbs
2935 lbs/ 40 psi / 5389 lbs
3068 lbs/ 42 psi / 5634 lbs
3201 lbs/ 44 psi / 5878 lbs
3334 lbs/ 46 psi / 6122 lbs
3467 lbs/ 48 psi / 6365 lbs
3599 lbs/ 50 psi / 6608 lbs
3731 lbs/ 52 psi / 6850 lbs
3862 lbs/ 54 psi / 7092 lbs
3994 lbs/ 56 psi / 7333 lbs
4125 lbs/ 58 psi / 7574 lbs
4256 lbs/ 60 psi / 7814 lbs
4387 lbs/ 62 psi / 8054 lbs
4517 lbs/ 64 psi / 8294 lbs
4647 lbs/ 66 psi / 8533 lbs
4777 lbs/ 68 psi / 8772 lbs
4907 lbs/ 70 psi / 9011 lbs
5037 lbs/ 72 psi / 9249 lbs
5167 lbs/ 74 psi / 9487 lbs
5296 lbs/ 76 psi / 9724 lbs
5425 lbs/ 78 psi / 9961 lbs
5554 lbs/ 80 psi / 10198 lbs referencepress
5683 lbs/ 82 psi / 10435 lbs
5812 lbs/ 84 psi / 10671 lbs
5940 lbs/ 86 psi / 10907 lbs
6069 lbs/ 88 psi / 11143 lbs
6197 lbs/ 90 psi / 11379 lbs / maxcold sometimes
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Old 02-23-2023, 03:41 PM   #30
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The correct inflation pressures for original equipment tires fitted to vehicles built under the guidance of FMVSS standards are found on the vehicle certification label, the tire load and inflation placard and in the vehicle owner's manual. Sometimes, not very often, vehicles may have a supplemental placard affixed next to the load & inflation placard. Usually, it's there on half ton pick-up trucks that have OE Passenger tires.

The FMCSA standards are written for the trucking industry and are not interchangeable with FMVSS standards.

Background: Tire manufacturers design and build tires to serve the needs of the industries where they are used. Vehicles built under the guidance of FMVSS have OE tires fitted to them by the vehicle manufacturer. The vehicle manufacturer has the sole responsibility for OE tire selections and fitments.

Original Equipment Tires fitted to RV trailers and all other FMVSS built vehicles are considered by NHTSA to be a minimum standard. Therefore, the tire industries standard for replacement tires is: NEVER use tires smaller than the OE tires. The replacement tires MUST provide a load capacity equal to or greater than the OE tires provided.

Load index numbers on ST & LT tires are there for the sole purpose of identification of a speed letter, such 94S. The official load capacity for ST & LT tires is the load range lettering system.

President Trump threatened offshore ST tire manufacturers with increased tariffs if they did not start identifying tire speed ratings. He gave them two options, comply with NHTSA lettering standards or mold the tire speed rating on the tire sidewall.

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Old 02-23-2023, 04:05 PM   #31
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Well, we have covered this ground before... many times; the horse is DEAD. Thanks to all the experts who have chimed in but for the layman, such as myself, I will inflate my tires which are OEM spec to the values in the white/yellow placard in my door frame.
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Old 02-23-2023, 04:10 PM   #32
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Okay, now that we have the facts corrected. Will 65 psi be sufficient?
2021 Ram Larmine 3500 HO = Tow vehicle
2019 Keystone laredo LA 325RL
Dry weight #10,990
Payload capacity #2010
GVWR #13,000
Hitch weight #1910
Assume @1000 extra weight in fifth wheel... tanks, etc.

Now the placard on door panel states tire and load information #5224, Assume truck has additional added inside weight of #400


Bridgestone Duravis R500 HD tire size for its maximum tire inflation and load capacity

LT235/80R17/E 120/117 tire with load range E and load index of 120 has a maximum single tire load capacity of 3085 lbs @ 80 psi, capable of supporting up to 3085 pounds or 1399 kilograms, while dual tire application with load index of 117 has a maximum dual tire load capacity of 2835 lbs @ 80 psi, capable of supporting up to 2835 pounds or 1286 kilograms when inflated to its maximum air pressure of 80 pounds per square inch (psi) or 552 kilopascals (kPa).

Thoughts?
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Old 02-23-2023, 04:23 PM   #33
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The question is what does the placard inside your driver door say the tires should be inflated to? My 3500 says 80psi and I suspect yours does too. That being the case the inflation pressure, per the manufacturer, should be at 80psi. If you have a blowout, if you have an accident, if, if....and they find those tires are underinflated the fault comes to you. Why would you want to run tires below the pressure? Pulling an RV you want every bit of control/firmness you can get in those tires to keep everything stable along with trying to keep them from failing.
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Old 02-23-2023, 05:22 PM   #34
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Quote:
Originally Posted by Rving life View Post
Okay, now that we have the facts corrected. Will 65 psi be sufficient?
2021 Ram Larmine 3500 HO = Tow vehicle
2019 Keystone laredo LA 325RL
Dry weight #10,990
Payload capacity #2010
GVWR #13,000
Hitch weight #1910
Assume @1000 extra weight in fifth wheel... tanks, etc.

Now the placard on door panel states tire and load information #5224, Assume truck has additional added inside weight of #400


Bridgestone Duravis R500 HD tire size for its maximum tire inflation and load capacity

LT235/80R17/E 120/117 tire with load range E and load index of 120 has a maximum single tire load capacity of 3085 lbs @ 80 psi, capable of supporting up to 3085 pounds or 1399 kilograms, while dual tire application with load index of 117 has a maximum dual tire load capacity of 2835 lbs @ 80 psi, capable of supporting up to 2835 pounds or 1286 kilograms when inflated to its maximum air pressure of 80 pounds per square inch (psi) or 552 kilopascals (kPa).

Thoughts?
You're trying your hardest to make this far more complicated than it has to be, and the answer to your question in red is: What does your rear axle weigh? The placard recommended pressure has been established to support the tire rating for your axle/truck weights at maximum GVWR.

So, back to the "red question". If your truck is not overloaded, the placard pressure is adequate (proper) for your vehicle. If your truck is overloaded, then the pressure may not be adequate for your vehicle load.

THE ONLY WAY TO KNOW IS TO NOT "DO THE BLUE" and assume that you might, maybe be around 1000 pounds plus the pamphlet specs for your trailer, but rather a "real world weight" eliminates the "ASSUME" and gives you accurate, not ASSUMED weights so you can "KNOW" not "best guess" whether the pressure on the door sticker on your truck is correct.

It all boils down to "If your truck is at/under the GVWR and is properly loaded so you don't overload your rear axle, then the sticker pressure is correct. On the other hand, if you don't know what the real world weights are, then a trip to the nearest CAT scale will eliminate all the "what if" and "I think" and "What do you recommend" stuff....

If you do weigh your truck, you'll KNOW whether it is overloaded or within the ratings. That is the first step in whether the pressure (and the tires and the axle and the truck) are capable of supporting your trailer load.
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Old 02-23-2023, 07:18 PM   #35
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Quote:
Originally Posted by Rving life;529261[COLOR="Red"
]Okay, now that we have the facts corrected. Will 65 psi be sufficient?[/COLOR]
2021 Ram Larmine 3500 HO = Tow vehicle
2019 Keystone laredo LA 325RL
Dry weight #10,990
Payload capacity #2010
GVWR #13,000
Hitch weight #1910
Assume @1000 extra weight in fifth wheel... tanks, etc.

Now the placard on door panel states tire and load information #5224, Assume truck has additional added inside weight of #400


Bridgestone Duravis R500 HD tire size for its maximum tire inflation and load capacity

LT235/80R17/E 120/117 tire with load range E and load index of 120 has a maximum single tire load capacity of 3085 lbs @ 80 psi, capable of supporting up to 3085 pounds or 1399 kilograms, while dual tire application with load index of 117 has a maximum dual tire load capacity of 2835 lbs @ 80 psi, capable of supporting up to 2835 pounds or 1286 kilograms when inflated to its maximum air pressure of 80 pounds per square inch (psi) or 552 kilopascals (kPa).

Thoughts?

Just to add another thought; your facts aren't corrected. You list the pin weight of the trailer as 1910....that is empty brochure weight which isn't anything near what you will have.

I'm not sure what you are looking for or trying to accomplish but I can assure you that trying to run as low a pressure as you think you can with an RV in tow is a very bad idea. Some use an inflation chart, some use the placard, some check occasionally. If you are pulling a 5th wheel there is no reason to run lower than max pressure. Tire wear? Are you going to try to get MAX miles out of tires you have that kind of load on? Wait until you have 3/32nds hoping one doesn't blow? Comfort? There's no appreciable difference between max psi and whatever the load chart will say. Traction? With the the 5th on there that is a non consideration. So we're back to the question of why the manufacturer's required psi would be wrong??
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Old 02-23-2023, 09:12 PM   #36
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Originally Posted by CWtheMan View Post
The correct maximum load capacity for that tire is 3042# at 80 PSI.
Well you are wrong on that, the 235/80-17 E are 3,085 single and 2,835 dual.
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Old 02-23-2023, 11:42 PM   #37
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Quote:
Originally Posted by Rving life View Post
Okay, now that we have the facts corrected. Will 65 psi be sufficient?
2021 Ram Larmine 3500 HO = Tow vehicle
2019 Keystone laredo LA 325RL
Dry weight #10,990
Payload capacity #2010
GVWR #13,000
Hitch weight #1910
Assume @1000 extra weight in fifth wheel... tanks, etc.

Now the placard on door panel states tire and load information #5224, Assume truck has additional added inside weight of #400


Bridgestone Duravis R500 HD tire size for its maximum tire inflation and load capacity

LT235/80R17/E 120/117 tire with load range E and load index of 120 has a maximum single tire load capacity of 3085 lbs @ 80 psi, capable of supporting up to 3085 pounds or 1399 kilograms, while dual tire application with load index of 117 has a maximum dual tire load capacity of 2835 lbs @ 80 psi, capable of supporting up to 2835 pounds or 1286 kilograms when inflated to its maximum air pressure of 80 pounds per square inch (psi) or 552 kilopascals (kPa).

Thoughts?
I assumed the opening question was for your towing vehicle. Can you give GAWR's and GVWR for TV? But correct me if wrong.

Then search GAWR's back in my made list, and I suspect it could be suprisingly low ( 45psi rear!? ).
Reason then is because OEM tires are yust P-tires with 35 psi recomended and reference-pressure. And has your TV single or dualload rear axle.


Is your 2019 Keystone a traveltrailer or a 5thwheel?
13000lbs GVWR for TT needs minimum 10% on hitch so 1300 lbs, maximum 15% = 1850 lbs.
So the 1900 lbs empty or max ( whatever) suspects a 5thWh wich allowes up to 25% of total weight on hitch.

Then the hichweight is practically above the rear axle of TV and 1900lbs gives practically 1900 lbs extra on rear axle.

If TT hich about 1/3th of wheelbase behind rear axle, wich gives if so, 25% more then 1900lbs more weight on rear axle, and lifts up 25% of 1900 lbs of front axle TV, if no WDH used.

If you give also specifications of TT or 5thwh's tires, I can make a list for those too.

And in post # 28 the 3042 lbs is old system, as I described in my post #23, so to my opinion the 3085 lbs is right as maxload belonging to loadindex 120 1400kg maxload converses to 3086 lbs .
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Old 02-24-2023, 01:40 AM   #38
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Originally Posted by rhagfo View Post
Well you are wrong on that, the 235/80-17 E are 3,085 single and 2,835 dual.
I doubt you read about tires more than I do. In the 2010 tire rules committee meeting The Laod Range Lettering system was confirmed to be the official rule for LT and ST tires.

There are no LT or ST tires with the designation 235/80R17. The "E" after a tire size designation with prefix ST or LT is the load range letter for that tire. You just cannot have a pick and choose maximum load capacity rating. The load range letter for that tire has a maximum load capacity of 3085# at 80 PSI. Double standards are not acceptable.

Read the information on the tire sidewall. It will tell you what the PSI rating is for that tire and the amount of load capacity it will support.

I found one in a Toyo load inflation chart.
LT235/80R17 Single 1725 1895 2055 2270 2370 2515 2680 2805 2940 3085 (E) 120

In written information about tires, the size is normally referred to as size. However, all of our tires are identified by designated size. So, when getting specific the whole designated size must be identified.

These are the most commonly used tire designated size prefix.

P-Metric
• Metric (a.k.a. Euro-Metric)*
• LT-Metric
• LT High Flotation
• LT Numeric
• European Commercial Metric (C-Type)*
• ST Special Tire for Trailers
• T-Type Temporary Spare

* Metric tires do not have an alpha character prefix in the size designation.

Make sure you're using the proper load inflation chart.
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Old 02-24-2023, 03:22 AM   #39
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Question is if on topicstarters tires LT is given in front of sizes. If not, its an european system tire, wich mostly also give E-load, LRE on sidewall, but thats only because DOT requires that to sell them in US.
In the list he has, at 80 psi most likely a loadcapacity of 3085 is given.
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Old 02-24-2023, 06:32 AM   #40
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Quote:
Originally Posted by sourdough View Post
Just to add another thought; your facts aren't corrected. You list the pin weight of the trailer as 1910....that is empty brochure weight which isn't anything near what you will have.

I'm not sure what you are looking for or trying to accomplish but I can assure you that trying to run as low a pressure as you think you can with an RV in tow is a very bad idea. Some use an inflation chart, some use the placard, some check occasionally. If you are pulling a 5th wheel there is no reason to run lower than max pressure. Tire wear? Are you going to try to get MAX miles out of tires you have that kind of load on? Wait until you have 3/32nds hoping one doesn't blow? Comfort? There's no appreciable difference between max psi and whatever the load chart will say. Traction? With the the 5th on there that is a non consideration. So we're back to the question of why the manufacturer's required psi would be wrong??
Well with a SRW running at or near Max pressure makes sense, although I ran the LT265/70-16 on our 2001 Ram 2500 at 75 psi, as I didn't need all the capacity, even that was a bit high for the axle weight.

Now as with OP and myself with a DRW, the LT235/80-17 has a dual capacity of 2,835# ea. at 80 psi. That is a total of 11,340#. Loaded I carry about 7,200# on the rear axle, this is about what the OP would carry. That is an excessive capacity of 4,140# making the tires overinflated for the load, and reducing traction. My rear axle is rated at 9,750# at a tire inflation of 65 psi ( this is from the tire inflation/payload sticker!). I run at about 55 psi as I am still 2,550# less than the axle rating.

I had a neighbor who ran log trucks, ran his tires at 10 or 20 psi less than max inflation, Why? when running at max the logging road rock was cutting the the tread terribly and loosing chunks. At the lower pressure far fewer cuts and no blowouts, or tread loss.
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