tow vehicle tire pressure

[macj9697]

The tires on my F150 have a max pressure of 44psi. I generally keep the tires at 35psi. Does it make any difference in towing ability to have the tires at full pressure. your thoughts???

[christid01]

I would think you would want to keep the tires inflated to vehicle manufacturer's specifications, usually located on a panel inside the drivers side door, but definitely in your owner's manual. The owner's manual may also discuss increase in tire pressure when towing, I think I will read up on that in my own before heading out this season. Good question!

[JohnB]

Hi Mac

TV tire pressure can make or break a stable towing rig. For towing stability you need a stiffer side wall tire to not have the truck wiggle due to soggy side walls. If you go to the back of the truck and just plan rock the truck back and forth you can see the sogginess. Look at the tire rim and the tire. The rim is stiff the side wall is flexing. P rated tires of some brands and types have it really bad as what works great for cursing does not for towing a TT. Even certain brands and type of LT tires have the same problem. Since they do not rate a tire by side wall stiffness this get really hard for someone figure out what to buy when getting new tires.

Here are some guidelines for air pressure when towing a TT that I go by and have found thru my experiences.

• A must for a minimum is that the tires are at the stated pressure on the drivers door sticker. This allows the tires axle loads to meet what the truck was rated for.
• It is common practice when towing a TT that the tires be inflated higher then door sticker to help create a stiffer side wall for increased towing stability. You should not ever go above the max cold side wall pressure listed on the tire. Your adjustable range is from the door sticker pressure up to the max side wall cold pressure.

For item 2 the question comes, well what pressure do I try? This becomes an experiment as the truck suspension, the brand and type of tire, the loaded TV and the size and load of the TT, what type of anti sway control all play into this stability issue. Some folks may never have a problem and can’t figure out why you do…. And often time this is the case but not always. I have seen this getting harder now a days that the TV manufactures keep refining the ride quality and that forces tire manufactures to have certain better ride characteristics. Tires of today just plain ride a lot better then they use to.

A place to start is air up the rear when towing. You can go right to max side wall cold pressure or go up in 5 psi jumps. The trade off is harsher ride verses stability. If you are on P tires that door sticker at 35 and you mayb only be able go to 44psi max as that is what that specific tire is rated for, then you only have 2 jumps to even try.

The front is more an experiment then the back. Full max pressure might be so hard on your style suspension that the truck literally bounces left to right and that is not good. Again with 5 psi jumps up you can start to feel better and some times worse. In the case of LT tires the front might be OK at door sticker as the tire is stiffer to start with, but again this all depends on the brand and tire loads and the truck itself. I know on my K2500 Suburban when I changed tire brands I use to run door sticker on the front and it was rock solid. Then on the new brand tires I had an instability that never existed when high side winds hit the TT. In that trucks case I could not go to max cold as the truck would bounce and actually jump left to right if I went above 70 psi. Could not get to 80 psi max. In this case 50 was door sticker and 60 psi made a global shift to better. I ended up at 65 as the best it could be. The rear was at max side wall.

Others with the same new tire on F250 PSD can run 75 no problem. That heavy engine changes the loads and he had different front end suspension. Again, an experiment.

If you are looking at a guess to start with, try door sticker front and rear if you are on P tires and a TT tongue weight of 500#. If you are 700# tongue weight or higher, put the rear at max cold as a starting place. The front take up by 5 psi and try it. You then have to tweak the front up a little or the back very lightly less to get the best combo. What I do it I start out higher and take an air gage with me. If it gets to hard/bad, I can tweak it down a few psi at the next rest stop. Adding means you need a compressor.

You can air the tires back down when not towing to get the cushy ride back again.

Hope this helps

John