Truck tire pressure

[Dennis878]

What should my tire pressure be when towing?

My truck Ram 1500 door sticker shows the tires PSI should be 38. It also shows a max payload weight of about 1400 pounds. Is the max 1400 payload based on the 38 PSI? The tire information shows 50 PSI to carry maximum load. What weight should my tires be when towing my trailer? Rockwood Mini Lite 2104s approx. 7000 pounds.

[Mandog]

Originally Posted by Dennis878

What should my tire pressure be when towing?

My truck Ram 1500 door sticker shows the tires PSI should be 38. It also shows a max payload weight of about 1400 pounds. Is the max 1400 payload based on the 38 PSI? The tire information shows 50 PSI to carry maximum load. What weight should my tires be when towing my trailer? Rockwood Mini Lite 2104s approx. 7000 pounds.

This is a highly contested subject. Your truck was tested and designed to perform at 38psi in the tires but I highly doubt they tested it at the max load. I’d run 45 psi front and rear on these tires. I suspect they are P rated?
In my opinion the smart thing to do would be install LT tires. They are designed to handle loads much better than P rated tires. You will feel the difference in a good quality LT tire. You may suffer a little in ride quality and MPG but it’s worth the extra safety it gives you. I run Cooper Discovery AT3 LT 10 ply. They have been great. Just my thoughts as towing puts a lot of stress and heat in a tire.

[The Big Toe]

Originally Posted by Dennis878

What should my tire pressure be when towing?

My truck Ram 1500 door sticker shows the tires PSI should be 38. It also shows a max payload weight of about 1400 pounds. Is the max 1400 payload based on the 38 PSI? The tire information shows 50 PSI to carry maximum load. What weight should my tires be when towing my trailer? Rockwood Mini Lite 2104s approx. 7000 pounds.

Where does it say your tires should be at 50 PSI for maximum load? Are they P-Metric tires?

Most of the time, C Range tires are rated at max load right at 35-36 PSI.

For some applications, you can inflate them to max load but those are usually for certain performance applications and have nothing to do with load carrying ability.

https://www.tirerack.com/tires/tiret....jsp?techid=55

[Dennis878]

My tires are Wildpeak AT Falken made in Thailand. These are factory tires as far as I know. Mud and Snow load range C. Thread 2 ply polyester and 2 steel, sidewall 2 ply polyester. Not sure what this mean but the max load single is 2535 pounds @ 50psi. The max payload dual is 2335 pounds @ 50 psi.

These numbers also 113/11OS.

[AlaskaErik]

My truck came with P rated ties and the door sticker says to keep them at 35 psi, which is what I do. I have had absolutely no tow issues with that.

[The Big Toe]

Originally Posted by Dennis878

My tires are Wildpeak AT Falken made in Thailand. These are factory tires as far as I know. Mud and Snow load range C. Thread 2 ply polyester and 2 steel, sidewall 2 ply polyester. Not sure what this mean but the max load single is 2535 pounds @ 50psi. The max payload dual is 2335 pounds @ 50 psi.

These numbers also 113/11OS.

Sounds like your tires are XL rated.

[clarkbre]

The answer is within the below link.

The problem is, you have to read it and know the weight on the axles of your truck.

It's much simpler to just allow a bunch of uncalculated opinions suggest the "right" PSI.

Load & Inflation Table Application Guide

For reference, the F250 in my signature calls for 65psi on all 4 corners. Changing from 275/70r18 to 295/60r20 tires and knowing the weight on each axle of my truck while it's towing, I've aadjusted down to 55 psi. It rides much more comfortable and the tires still are able to carry more than the GVWR of the truck.

[Tireman9]

Originally Posted by The Big Toe

Where does it say your tires should be at 50 PSI for maximum load? Are they P-Metric tires?

Most of the time, C Range tires are rated at max load right at 35-36 PSI.

For some applications, you can inflate them to max load but those are usually for certain performance applications and have nothing to do with load carrying ability.

https://www.tirerack.com/tires/tiret....jsp?techid=55

LR-C would be on the Placard and LR-C Max load capacity is with the tires at 50 psi not at 35-36 which is the pressure for max load for most P-type tires.

[Tireman9]

Originally Posted by The Big Toe

Sounds like your tires are XL rated.

If the tires are P type they can be XL but the tire would say "XL on it's sidewall.


XL is only used on P type tires.

[Tireman9]

Originally Posted by Dennis878

My tires are Wildpeak AT Falken made in Thailand. These are factory tires as far as I know. Mud and Snow load range C. Thread 2 ply polyester and 2 steel, sidewall 2 ply polyester. Not sure what this mean but the max load single is 2535 pounds @ 50psi. The max payload dual is 2335 pounds @ 50 psi.

These numbers also 113/11OS.

This additional info helps. You do not have duals on the rear so we can ignore that tire info.


Your tires size starts with "LT" then sizing numbers and it has a "C" toward the end. We can only guess Maybe LT365/75R16 C ?


Side not to all asking about tires & inflation. It is really helpful if you provide the complete tire size and Load Range.. Better yet a picture of the vehicle certification sticker AKA Tire Placard from the door jam. Can save us all some time asking for the basic info.


Finally knowing your actual load on your tires from a truck scale reading for EACH axle would be great.

[Dennis878]

This is from the door post.

[Tireman9]

Originally Posted by Dennis878

Attachment 246809

This is from the door post.

OK That helps a lot. I would suggest you inflate your tires to 38 psi cold.


Also look for a local truck scale (truck stop or local feed store or local gravel or building supply) With the truck and trailer fully loaded get on the scale to confirm you have not overloaded any of your tires. (truck or trailer). Check the weigh on each axle. do not get the truck weight and divide. Same with the trailer. Each axle separate weight as few RVs have an exact 50/50 weight split.

Ideally the measured load on the tires should be no more than 85% of the load capacity found in Load & Inflation tables for the truck tires or the Trailer tires.

[The Big Toe]

Your tires will have their maximum load-carrying capability at 38 PSI. You can inflate them to the max that it says on the sidewall but I can't imagine why you'd want to; unless you're planning on running a road race or testing it on a skidpad.

I don't know why they do that. On my Goodyear F1's, I can see it but on a truck tire, I don't get it.

[BigH]

Originally Posted by The Big Toe

Your tires will have their maximum load-carrying capability at 38 PSI. You can inflate them to the max that it says on the sidewall but I can't imagine why you'd want to; unless you're planning on running a road race or testing it on a skidpad.

I don't know why they do that. On my Goodyear F1's, I can see it but on a truck tire, I don't get it.

Actually the vehicle in question will be able to operate at its maximum weight rating with 38lbs in the tires.

The tires are capable of their max capacity as listed on the sidewall of the tire.

Its possible but I have never seen a vehicle tire placard on a 1/2 ton truck that uses the max side wall pressure stated on the tire as the suggested tire pressure.

[Tireman9]

Originally Posted by The Big Toe

Your tires will have their maximum load-carrying capability at 38 PSI. You can inflate them to the max that it says on the sidewall but I can't imagine why you'd want to; unless you're planning on running a road race or testing it on a skidpad.

I don't know why they do that. On my Goodyear F1's, I can see it but on a truck tire, I don't get it.

Sorry but the max load for LT275/65R18 LR-c tires is 2,535 single when inflated to 50 psi.


The load table does not show 38 psi but the tire is rated for 1,940# @ 35 psi and 2,130 @ 40 psi according to industry tables. So clearly these tires do not have their maximum load carrying ability at 38. Now the truck may have a GAWR of about 4,100# but that isn't the question we are trying to answer in this thread.

[Dennis878]

Ok very confusing information here or just different opinions. Maybe I can clear this up a little. At the factory PSI setting, 38, with stock tires information from door post is this the setting for max weigh capacity? Several of you say yes and the other no. Tireman9 in one post you say set at factory setting then you say no in another. Regardless of my truck axle weights what is the 50 PSI rating on the tires mean if the factory setting is the max weigh my truck can handle and no more. I think I’m confusing myself here.

[BigH]

Originally Posted by Dennis878

Ok very confusing information here or just different opinions. Maybe I can clear this up a little. At the factory PSI setting, 38, with stock tires information from door post is this the setting for max weigh capacity? Several of you say yes and the other no. Tireman9 in one post you say set at factory setting then you say no in another. Regardless of my truck axle weights what is the 50 PSI rating on the tires mean if the factory setting is the max weigh my truck can handle and no more. I think I’m confusing myself here.

Its not an opinion that your truck will handle the maximum weight rating at the posted psi on your tire and loading sticker...38psi. Your tires are capable of more than your vehicle...it that simple.

That said, in every half ton I owned, I preferred the max pressure listed on the sidewall of the tire if I was near the vehicles max weight for the rear tires.

[ependydad]

Originally Posted by Dennis878

Ok very confusing information here or just different opinions. Maybe I can clear this up a little. At the factory PSI setting, 38, with stock tires information from door post is this the setting for max weigh capacity? Several of you say yes and the other no. Tireman9 in one post you say set at factory setting then you say no in another. Regardless of my truck axle weights what is the 50 PSI rating on the tires mean if the factory setting is the max weigh my truck can handle and no more. I think I’m confusing myself here.

The confusion comes with "maximum weigh capacity" as there are multiple weights that this can refer to.

For the maximum carrying capacity of the tire, you should use the max cold PSI on the sidewall of the tire.

Using the maximum carrying capacity of the tires added together will be higher than the maximum carrying capacity of the axle that connects to those tires. That rating is called the "Gross Axle Weight Rating" (GAWR).

The maximum carrying capacity of the truck is called the "Gross Vehicle Weight Rating" (GVWR). This is going to be lower than the sum of the GAWRs and lower than the maximum carrying capacity of the tires.

Confused yet?


My bet is that the 38 psi corresponds with the tire's carrying capacity to support the axle's maximum weight rating.


There's a sticker on the doorjamb that will tell you what the GVWR and GAWR are.

[The Big Toe]

Originally Posted by Tireman9

Sorry but the max load for LT275/65R18 LR-c tires is 2,535 single when inflated to 50 psi.


The load table does not show 38 psi but the tire is rated for 1,940# @ 35 psi and 2,130 @ 40 psi according to industry tables. So clearly these tires do not have their maximum load carrying ability at 38. Now the truck may have a GAWR of about 4,100# but that isn't the question we are trying to answer in this thread.

Interesting. You learn something new every day. Didn't realize it was an LT tire. Thought it was a typical C. Unusual to find an LT tire on a 1500.

If I had paid closer attention, the door jam sticker clearly says 'LT'

My bad

[Dennis878]

My axle weight maximums I assume.