Forum Discussion

nagel's avatar
nagel
Explorer
Jul 14, 2019

Tow Vehicle Tire Pressure

Do others increase / decrease the tire pressure in their tow vehicle when they are pulling the trailer? My truck specs say 35 psi for all 4 tires, but nothing about adjusting when towing.

I'm thinking I want to increase the tire pressure in the rear tires maybe to 40 psi when pulling the trailer. Thoughts? Is their a formula for figuring this out or should I leave it at 35? I'm thinking with the added tongue weight, it could cause the tires to "smash down" a little bit.
  • When you air them up to their max, remember to account for heat. Aired mine to 77 PSI (rated for 80 PSI max). Coming back from a camping trip the display showed they were 88 PSI. Pulled over and lowered to 80 PSI. Account for heat!!!
  • I keep the wifes '16 1500 chevy crew cab short bed with P255/75-17 at 38psi in front towing a 10k trailer or empty. The door tag also says 35 psi all around.

    ...and the rears at max sidewall 44 psi when towing and 32 psi when empty. The tires have 45k+ miles now and should make another 10k before I retire them before hard winter sets in.

    I use the chalk line method on all my trucks to find the best ride and best long term wear for each truck (1500 chevy....2500 Dodge/Cummmins....and a '98 3500 DRW crew cab 4wd 454 gazz hogg.
  • I run 60/80 during towing season, drop it to 60 all around in the fall unless I end up towing something significant in which case I’ll air back up. The lower pressure in the winter provides a much nicer ride.
  • If your tires say max 35 they are likely P passenger car tires. I would recommend upgrading to LT Light Truck tires. They will have a stiffer side wall and perform better towing. Don't ever inflate over the MAX cold tire pressure listed on the side wall. If you got the 35 psi from the door sticker and the tires say 40 or 45 psi or something like that then I would absolutely go to the tire limit if you don't know your axle weights. However:
    Tire manufacturer's have load inflation tables. You just use the table to see what inflation pressure you need in the tires to support the weight they are carrying. Most vehicles do NOT need maximum tire pressure to support the actual weight on the tires. Going to MAX pressure "just because" is a great way to make the ride rougher. It could possibly also wear out the center of the tires faster if they are severely over inflated.
  • Yep, 1/2 ton GMC Sierra. Door sticker says 35 psi. I put E rated tires on that say max pressure 80 (due to towing trailer at times). If I air up tires to 45 psi unloaded (no trailer) it shakes the truck to death above 60 mph, but good with 35 psi. Weird.

    Anyway, getting ready for a trip next weekend and in the past pumped up the rear tires to 45 psi when towing, but no science behind it. I looked up the tires and they 3,xxx at 80 psi.
  • Yep I air the TV tires to the max. Stiffens the tire side walls. Keeps them from flexing, and helps keep the TT from moving the TV around
  • I run the recommended psi via door sticker when not towing and maximum psi in truck and trailer when towing.....added cold of course.
  • I always run the recmmended pressures listed on my door pillar, loaded or empty, in my case, 65 psi in the front, 80 in the back. I never exceed those presssure ratings. The engineers who designed and the people who built my pickup know way more about what is correct than I do.
  • I inflate my E load rated tires to 80 PSI (max PSI listed on the door sticker) when I tow but I never exceed the recommended PSI. 35 PSI seems rather low...I'm assuming your truck came with P load rated tires.
  • I increase my Tahoe’s rear tires to maximum cold air pressure when towing...which gives me their maximum weight capabilities.