"LT" tire pressures on Expedition

[Rustycamperpant]

I moved up from "Heavy Load" tires on my Expedition to real "LT" tires. Max air pressure on the new tires is 80#, max pressure on the heavy load tires was 50#. I always ran my other tires at max pressure when towing my TT.

I talked to the tire installer and asked him what they set the pressure at and he responded, "To whatever is specified on the door sticker". This will be in the 36 - 38# range.

What do you all do? I was thinking all along I should run much higher pressure on the LTs just like I did on the heavy load tires. Thanks in advance...

[CapriRacer]

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.

[MFL]

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]

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.

[Rustycamperpant]

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.

[Ductape]

What is the pressure rating for your wheels?

[azdryheat]

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.