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Old 06-12-2019, 08:57 AM   #1
jmw920
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Truck Tires XL load rating pressure?

Have a question about tire pressure.
New to the scene but towing a 2020 Passport 2820BH GT with a 2019 Ram 1500.
Specs on truck are towing of 11,340 and payload of 1,840.
GVWR of TT is 7200. Tongue weight should be around 860lbs based on the GVWR of the TT.

Door sticker says inflation at 32psi, Tire says max PSI 51 and Max Load 2535lbs.


So now the question. Should I keep my tires inflated to 32psi cold or the 51psi cold per the tires marking or somewhere in between?
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Old 06-12-2019, 09:16 AM   #2
Canonman
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Just my opinion, but you should upgrade your truck tires to an LT, load range E, 80psi tire. What you have now is probably a "P" passenger type tire and will be VERY squishy when you're towing. Looks to me like you're well within the truck specs but the weak link will be the tires
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Old 06-12-2019, 09:29 AM   #3
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I agree with canonman. The P tires are meant more for a nice, soft ride in your 1500, not towing a large trailer. They will squish, mush and slide back and forth with the load on them. LT tires will eliminate much, if not all, of that. If you tow with the P tires run the rears at max inflation to minimize all the squishiness as much as possible and run the fronts at max or maybe mid 40s......but, I would just get LT tires and run them at 80psi - if your wheels will handle it.
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Old 06-12-2019, 10:06 AM   #4
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IMO your truck’s manufacturer isn’t going to tell you a weight you can tow with that truck and then put tires on there that are unsafe for that task. However, they may have a notation in the truck’s owner’s manual about what to inflate those tires to when towing something heavy.

With those tires, owners are normally going to inflate them to 51 PSI for more stability. And, remember, the maximum load capacity on the tire sidewall needs to be divided by 1.1. That will give you the official derated maximum load capacity for those tires when used on your truck.
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Old 06-12-2019, 10:35 AM   #5
jmw920
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Thanks all.
So i went on Falken website to verify and the tires are 6ply as are the LT tires.
So not sure why these arent LT.
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Old 06-12-2019, 11:13 AM   #6
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Originally Posted by jmw920 View Post
Thanks all.
So i went on Falken website to verify and the tires are 6ply as are the LT tires.
So not sure why these arent LT.
I think you'll find that even in LT tires (yours are P-metric tires) that load range C (6 ply) is considered "barely adequate" for heavy towing. Most would recommend LRD (8 ply) as acceptable and LRE (10 ply) as preferred tire ratings for heavy towing. Essentially LT tires have "stiffer sidewalls", less "squiggle" when loaded heavy and perform with more stability than P metric tires. Much of that is based on higher operating pressure, about 30 psi more than your maximum rated pressure. Trying to compare P metric and LT tires is much like comparing SUV's with station wagons. They all "look kind of alike" but that's about the end of the similarities.... Same with P metric and LT tires.
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Old 06-12-2019, 03:49 PM   #7
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With those tires, owners are normally going to inflate them to 51 PSI for more stability. And, remember, the maximum load capacity on the tire sidewall needs to be divided by 1.1. That will give you the official derated maximum load capacity for those tires when used on your truck.
I have read much of your writings on this forum and have the upmost respect of your knowledge. The tires on my vehicles all have a Single and Dual load rating at 80psi. Where did this divided by 1.1 come from? "official" Who is official?
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Old 06-12-2019, 05:29 PM   #8
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I have read much of your writings on this forum and have the upmost respect of your knowledge. The tires on my vehicles all have a Single and Dual load rating at 80psi. Where did this divided by 1.1 come from? "official" Who is official?
The tire in question in this thread is a passenger tire fitted to a half ton truck. The FMVSS require such tires have their maximum load capacity reduced by about 10% when used on that pick-up-truck. The procedure is to divide the load capacity by 1.1. Each cold recommendation is calculated by the vehicle manufacturer.

LT tires in a dual configuration on dually trucks have a similar reduction, hence the "single/dual" maximum pressures shown on the tires sidewalls. The reasoning there is different, road crown is one of them.
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