Lazarus-F150

I feel really dumb having to ask this, but I've always been able to go to the door frame to find the answer.... How do I determine what tire pressure I should run on tires outside of the manufacturer's specs. Specifically, I am running 32" tires on on a '92 SWB 4x4. Any help would be appreciated.

Thanks!

memoniz

Does it not say on the tire?

Lazarus-F150

I've been told that the number on the tire is the maximum cold inflation pressure and not necessarily the optimal inflation pressure. Wrong? Right?

memoniz

Don't know. But as a one time tire buster for Kmart in the 80's, we always used that. Personally I like a firmer tire for easier role. Soft tires for better traction, Firmer tires for better mpg.

wde3477

The rating on the tire is the maximum cold inflation pressure, likely overinflated for most typical driving.


I have an Impala that recommends 32 psi. Since I do mostly highway driving with this vehicle, have found that 28-29 psi seems to be the ticket for obtaining even treadwear and related maximum tire life.


One suggestion would be to start at 32 psi or so, then closely watch your treadwear as an indicator whether to put a bit more or less into the tire. A lot of heavy loads or mostly city driving will likely demand more pressure, unloaded or mostly highway driving may call for a bit less.

flareside crazy

I run my truck at 35 psi, that's what most trucks will run the post above me is has good info but I worked at discount tire for a year and that just about what we put in every half ton truck unless they wanted max air pressure for towing and again the pressure the tire says is max psi, and your tires will go up 3 psi when your driving it and go back down 3 when its parked so put that in prospective as well

Just call me Sean

iTrader: (1)

I always put in the max listed on the sidewall, that way when I check it again six months later it's still at a decent pressure.

sdmartin65

I've seen a few posts on using a chalk method to determine the right pressure to get even tread wear. Do a search on it, makes sense and is easy to do.

fltdriver

I'm with Sean on this one, fill them to the MAX cold pressure or just under it. I check my pressure every week and it doesn't fluctuate too much but I've always been told "more psi for mpg and less for a smoother ride. Since I'd rather drag 1-2 mpg out of the truck rather than getting a mildly smoother ride I pump it up. Mine are kept between 45-50psi (50 being max cold).

Manuellabour247

It depends on the maximum pressure on the sidewall. I'll have to look, but there was another thread that was recommending 80% of maximum. I believe that was a heavy tire that the person would use for moderate towing though. I try to do 75% of the maximum as that has consistently given me the best tread wear and as smooth a ride as I can get since I pull a trailer once in a while. My max pressure is 50 on my tires. I have mine set at 37-38. I also check in the morning before the sun comes up to get a more accurate reading. To each their own though. If you want max mpg, I'd say go 3-5 psi short of max. If you want better ride, take it down. Do not go below the factory psi for the truck as you will have a warning light for low tire.