View Full Version : Tire pressure...How much


SSupermanZ
May 9th, 03, 04:59 PM
For some reason I keep my all my cars at 32psi
But today I noticed the tires on my H2 were low so I checked them and they were at 28psi.
I looked at the tires and they say max 50psi when cold...Door sticker says 38psi cold.
What the heck do I pump the tires to?
:confused:

CFunK
May 9th, 03, 05:42 PM
If it were my Hummer I would make sure all were at 38 psi cold.

The number on the door sticker is there for a reason.

DjD
May 9th, 03, 06:11 PM
This one could get heated... It did the last time it came up which was a real long time ago.

The rating on the side of the tire is the max cold safe pressure the tire is rated at. There is a weight factor that goes with the max pressure. If you are going to load the vehicle to the max the tires can handle safely, you need to set the pressure to the max recomended on the tire.

The sticker on the vehicle is the factory recomended pressure for your vehicle with the factory installed tires. That takes into consideration, traction, handling safty, braking and vehicle load recomendations. I belive any like load rating and size tire the vehicle manufactures rating is fine. If you tow or fill the back with rocks you can run up to the tires max rating on the tire.

Taking all this a step further, just like at the track you can adjust tire pressure to suit your driving style. I would refer back to the vehicles recomdation and adjust from there. Hard tires will get you less traction than slightly softer tires. Hard tires will get you better gas mileage (less rolling resistance)

On rear wheel drive cars that the rear wants to come around before the front pushes you can lower the rear pressure and increase the front to correct some for the rear wanting to kick out through a corner. It won't make your H2 an auto crosser but if you drive real agressive around corners it might give you a bit more control.

The minute you get away from the stock size and rating tire and wheel you have to disreguard the factory rating on the door sticker and you are on your own based on tire load and max psi rating...

SSupermanZ
May 9th, 03, 06:25 PM
Very good replies guys,
I dont tow anything with this truck or drive it around corners fast. I think I'll pump them up to 40psi and see how they do..
Thanks

pdq67
May 11th, 03, 04:50 AM
It's a factory cushey ride thing!

That's why Ford got into trouble with their SUV roll center and tire thing b/c they opted to lower the factory's recommended tire pressue a schosh which in turn dropped the roll center a schosh instead of widening it like they should have!!!

Bridgestone/Firestone took it on the chin b/c they didn't have the guts after 50 plus years of selling tires for Fords to tell them they needed to fix their problem and NOT mess with the tire pressures!!!!

AND to throw gasoline on the fire, Big Brother knew all along this was happening b/c one of the things NSHTA checks is the ratio of track width to roll center height!!!!!... That number is a directly correlation for vehicle stability regarding quick lane changing in an emergency siuation and roll-over tendencies!!!!!!!!

You know a cheaper way to do something!!! Anyway, the tires proved to be just slightly underinflated and Ford said it was for ride quality!!!

And the rest is history and 15,000,000 or so good tires thrown away!!!!!!!

pdq67

GMJim
May 11th, 03, 06:33 AM
I might suggest you keep an eye on tire wear. If the tires are wearing in the center more than the outside, then you have too much air in the tires for the type of driving you do. If they are wearing on the outside edges (evenly) then you don't have enough air in there. With the cost of H2 tires, I would follow the advise on the door sticker, and take the other opinions into consideration as well, but ultimately you want the whole tread width touching the pavement equally. Sometimes the best ride comes at the expense of new tires sooner than you want to buy them. :(
Jim