Tire Pressure with New Tires

[wkc22fb]

New tires on my F-150, YIPPEEE! TT is Jayflight 22FB with gear weighing in around 5200lbs with 500lb tongue weight (I think, maybe 800). Tires purchased are Michelin LTX LT275/65R18 "E" rated, max pressure of 80lbs. Tire shop said 50lbs "should be fine" with my towing load. Here lies my question: JOF members would you agree with 50lbs? And should I run higher pressure on rears?

Thanks!

[mohok1]

IMHO, I think max pressure as I have been told tires are manufactured to compensate for the temp build up. Harder ride but should ensure even tire wear. 30lbs under max could lead to the out and inside treads wearing sooner than the middle. Check out the manufacture's recommendation is for towing. Info should be available on the web. I run max 80 psi on my TT and 75 front 75 rear on my TV. I have a diesel with more weight on the front axle due to heavier engine.

[TWP723]

I'd say run them at about 65-70psi. At any pressure, make sure the sidewalls are not touching the ground. When tires are filled properly, the side tread should barely be touching the road. When loaded, the "pancake" should include a portion of the sidewall tread, but not all.

[jasoncw]

Don't run them at 80, that's overkill. You only need to run them at 80 when you are loading the rear axle at the full tire capacity (3,415 per tire if they are the A/T 2's). I would fill them between the door sticker and the max pressure when towing, and at the door sticker when not towing.

[wkc22fb]

I thought 80lbs was a little extreme also. That pressure rating is rated at 13,500lbs, no way would I attempt that with a 1/2 ton TV. I think I'll start at 70, easier to deflate than inflate if needed.

[hboy]

Check the minimum pressure recommended for the tire. I had a local shop tell me 55 psi was the minimum they recommended on their LT tire (firestone).

[tjpolsin]

Did you put these tires on stock rims? Check the pressure ratings for the rims as well. The pressure rating will either be stamped on the rim, or you will have to research Ford for answers.

Inflate your rear tires to max permissible (either tire or rim max) during towing season, then deflate when running empty. You will bounce less, and will get better wet road traction.

The TPMS on my 2500 RAM has setting for 70#full load and 45#light load. Those setting are for E rated tires like you have. Your tires will run at less than max pressure.

[Jagiven]

You can play around with the tire pressures and they do not need to be the same between the front and rear. My recommendation is start with the 50 psi, if the unit feels a bit wiggly, increase the rear tire pressure by 5 -10 psi, and the front by a little less. Don’t be afraid to try making a few changes. You may find while towing you will want a higher pressure, and when the TV is used as an everyday vehicle you might what a lower pressure.

My old tires on my Dakota where really nice, but were starting to weather check, so I bought a similar tire by a different manufacture. The handling with the HTT was horrible at OEM recommended tire pressure. After a few trips I found by increasing my rear pressure by 7 psi and front by 5. This took all the wiggle out of the truck that occurred after a tire change, and towing performance is very nice again.

[TWP723]

Oh, and use Nitro. Pressures stay consistent and don't change from season to season due to temperature changes. I'll never use air in my tires again.

[WIBadger]

I would recommend that you take your rig (when loaded) to a CAT scale (or something similar) and weigh your truck and trailer. Once you have some actual data, you can use that to follow Michelin's recommended psi rating based upon actual loads.

Below is the load and inflation table direct from Michelin (I think this is current info, but check the site to confirm):

LT275/65R18 (E-Rated) Table:

PSI LOAD AND INFLATION

35 1,940 lbs.
40 2, 130 lbs.
45 2,310 lbs.
50 2,535 lbs
55 2,660 lbs.
60 2,825 lbs.
65 3,000 lbs.
70 3,150 lbs.
75 3,305 lbs.
80 3,415 lbs.

As you can see, it is never a good idea to just go with a tire shop's or someone else's recommendation (eg, "50psi should be fine") unless you trust their wisdom.

[norty1]

Air is a mixture of 78% nitrogen, about 20% oxygen and assorted other gases. Because of the oxygen, it supports combustion. Its specific heat is 0.24 BTU per pound per degree Fahrenheit. Nitrogen is not able to support combustion. Its specific heat is 0.25 BTU per pound per degree Fahrenheit. Honestly, it doesn't make much sense to pay lots more for 0.01 more of BTU absorption!

Not enough difference to justify the expense unless you are driving a high speed race car. On a trailer or truck, nah!

First time you add air or if the place rips you off by not doing it correctly you have no way to go. Green caps! Whoopie

IMO, Nitrogen is the biggest consumer rip off since bottled water.

[TWP723]

I've had nitro in my truck since Dec. 1st and haven't lost anymore than a 1 lb. +/- in any of my tires. My F150 would lose a pound of air every month. The $14 it costs me to fill them with nitro is worth not having to go to the gas station every month or so to top off my tires. My TT needs air every time I pick it up from the yard. This past trip, I added at least a pound to every tire on the trailer. My truck, still good. Worth $14 to me.

[mohok1]

To clarify my earlier comment on T/P. I should should have been more specific on the 80 PSI. Was mainly addressing the TT. I just had my axles realigned at a Truck Rebuild Shop that has been in business 30 plus years. The owner said run the tires at 80 PSI on load range E tires which I have been doing for 20 years, so who do you believe. Still recommend calling the manufacturer customer service and address the issue. They mak!em. Would be interested to know what they say.

[norty1]

I put g614s on my trailer over a year ago. Never put any air in them yet. TP stays plus minus 2 lbs.
There are no laws against doing it any want you want.