"LT" tire pressures on Expedition

My door sticker says 70 front and 65 rear on the dually's. When I hook up my toy hauler I have 3500 pounds on the 5th wheel hitch and I don't change my tire air pressures. The tire inflation tables say I'm carrying the proper amount air pressure for the weight I'm carrying. The max air pressure rating on your tire is for the maximum weight that tire will be carrying. If your not carrying the maximum weight then there is no need for maximum air pressure.

Get your Expedition weighed and then check the weight against a tire inflation table or go by the door sticker.

What is the pressure rating for your wheels?

Ductape wrote:
What is the pressure rating for your wheels?

Thats a good question , I dont know. I have the stock 20" wheels on my truck. I used a air pressure guide for a tire installer and it looks like if I use 50 - 55# of pressure I should get all the capacity I need. (in the neighborhood of 2,335-2,360# per tire).

I also read that if I go above 60# I may blow out my valve stems. I think I will run at 50, maybe 55#. The stiffer sidewalls should make a nice difference.

Rustycamperpants wrote:

Ductape wrote:
What is the pressure rating for your wheels?

Thats a good question , I dont know. I have the stock 20" wheels on my truck. I used a air pressure guide for a tire installer and it looks like if I use 50 - 55# of pressure I should get all the capacity I need. (in the neighborhood of 2,335-2,360# per tire).

I also read that if I go above 60# I may blow out my valve stems. I think I will run at 50, maybe 55#. The stiffer sidewalls should make a nice difference.

Be careful what you read on forums, especially RV ones. You're not going to blow out a valve stem by airing up to 60 lbs, or even 120 lbs, nor will your factory OEM wheel grenade. The pressure rating of your OEM wheel, if it even has one, will be more than the pressure any tire requires that will physically fit on it along with a substantial margin for safety/ error. Don't inflict yourself with a case of Rv board OCD.

Rustycamperpants wrote:

Ductape wrote:
What is the pressure rating for your wheels?

Thats a good question , I dont know. I have the stock 20" wheels on my truck. I used a air pressure guide for a tire installer and it looks like if I use 50 - 55# of pressure I should get all the capacity I need. (in the neighborhood of 2,335-2,360# per tire).

I also read that if I go above 60# I may blow out my valve stems. I think I will run at 50, maybe 55#. The stiffer sidewalls should make a nice difference.

I think you are figuring right to run tires at 50-55 psi. Since you can compare how the trailer towed before, to how it tows now, you can adjust accordingly. Yes, the wheels will have a load rating, and tires/wheels designed for 80 psi, normally have higher rated valve stems. IMO, if you need more psi, due to handling, wanting stiffer sidewalls, you should be good to 65 psi, with no worries.

Jerry

Ralph Cramden wrote:
Be careful what you read on forums, especially RV ones. You're not going to blow out a valve stem by airing up to 60 lbs, or even 120 lbs, nor will your factory OEM wheel grenade. The pressure rating of your OEM wheel, if it even has one, will be more than the pressure any tire requires that will physically fit on it along with a substantial margin for safety/ error. Don't inflict yourself with a case of Rv board OCD.

Yup, be very careful what you read on internet forums - including the post above. If the installers used regular valve stems (Why wouldn't they?), the valves CAN be blown out by excessive pressure. In the case of regular passenger car valves - the kind your vehicle came from the factory with - the max pressure is 65 psi. It is likely the installers used the same kind.

And to answer your question, I have to ask a question: What was the size of the tire that came originally on your vehicle and what pressure was specified for it? And what size did you replace them with? Without those numbers, no one can tell you what pressure to use.

BTW, there should be a sticker on the driver's doorframe - commonly called the vehicle tire placard - that will list the original tire size and the pressure specified for that size. The replacement size can be found on the sidewall - and be sure to include the letters in front of an/ore behind the size. Those numbers tell what kind of tire and affect what pressure to use.

Assuming for the moment you replaced the original P metric tires with LT tires with the same dimensions, the LT tire requires 15 psi more than the P metric tire to carry the same load.

Ralph Cramden wrote:

Rustycamperpants wrote:

Ductape wrote:
What is the pressure rating for your wheels?

Thats a good question , I dont know. I have the stock 20" wheels on my truck. I used a air pressure guide for a tire installer and it looks like if I use 50 - 55# of pressure I should get all the capacity I need. (in the neighborhood of 2,335-2,360# per tire).

I also read that if I go above 60# I may blow out my valve stems. I think I will run at 50, maybe 55#. The stiffer sidewalls should make a nice difference.

Be careful what you read on forums, especially RV ones. You're not going to blow out a valve stem by airing up to 60 lbs, or even 120 lbs, nor will your factory OEM wheel grenade. The pressure rating of your OEM wheel, if it even has one, will be more than the pressure any tire requires that will physically fit on it along with a substantial margin for safety/ error. Don't inflict yourself with a case of Rv board OCD.

I usually ignore idiots of this sort, but the OP and anyone else interested in uprating tires would do well to educate themselves as to the facts about wheel pressure and load ratings.

I'll have no further comment, life's too short to debate with people who are willfully ignorant and choose to provide dangerous advice.

Ductape wrote:

Ralph Cramden wrote:

Rustycamperpants wrote:

Ductape wrote:
What is the pressure rating for your wheels?

Thats a good question , I dont know. I have the stock 20" wheels on my truck. I used a air pressure guide for a tire installer and it looks like if I use 50 - 55# of pressure I should get all the capacity I need. (in the neighborhood of 2,335-2,360# per tire).

I also read that if I go above 60# I may blow out my valve stems. I think I will run at 50, maybe 55#. The stiffer sidewalls should make a nice difference.

Be careful what you read on forums, especially RV ones. You're not going to blow out a valve stem by airing up to 60 lbs, or even 120 lbs, nor will your factory OEM wheel grenade. The pressure rating of your OEM wheel, if it even has one, will be more than the pressure any tire requires that will physically fit on it along with a substantial margin for safety/ error. Don't inflict yourself with a case of Rv board OCD.

I usually ignore idiots of this sort, but the OP and anyone else interested in uprating tires would do well to educate themselves as to the facts about wheel pressure and load ratings.

I'll have no further comment, life's too short to debate with people who are willfully ignorant and choose to provide dangerous advice.

Go down to your local tire place and ask the owner if he blows out many valve stems or has OEM wheels blow apart when he seats beads. I'll refrain from returning the favor and calling you an idiot, as you've made it quite clear that you are. Thanks for having no further comment. Go pop open another Ensure.

To the OP, you'll likely not get close to the loads that require max pressure on an E load tire. The beauty of heavier tires than needed on a lighter duty truck/tow rig, is having the headroom for anything you'll carry or haul, stiffer sidewalls and tougher tires in general and longer tread life than the same P or XL rated tire.
Remember, it's air that holds the vehicle up, not tires. Air pressure needed is a function of load. Run whatever pressures you need for the weight you're carrying. Want a little softer ride, stay on the low end of the needed pressure for the weight. Want a more solid, better handling ride, adjust up some from what is needed.
Door stickers are 1 size fits all guidelines and liability coverage for the mfgs against those who don't understand and are sue happy. That is all.

BTW, I also believe, within reason, that you cannot blow up a good rim or valve stem, or tire for that fact. This is not scientifically proven, but rather from many years of doing more with less when needed. I routinely run 55-60 psi in the rear tires of half tons with 44psi "max" tires when towing heavy. Freeway speeds, mountain passes, frost heave riddled highways, etc. it works.

Also, not scientific, but general industry liability assumption....Yes ALL mfgs look to shave costs to increase margins, AND recognize liability as a big part of the risk matrix when designing a component or an entire product.
Tires and wheels get abused to no end, by EVERYONE, intentionally or not. And they're one of a few major components of a vehicle, that if they fail, at speed, have a high likelyhood of the literal fiery crash. Add axles, springs, brakes and steering components into this. No one dies if the AC quits working at 80mph. Someone does if the tire quits working at 80 mph.
Based on this and my previous post, there is a large factor of safety built into tires and rims.
Something to think about.