Tire pressure

The side of my tires read 32-35

JD

Doc

I agree with Doc, ~34 psi.

Cheers

"Martin Riddle"

lol

on my 81 firebird 295/50/15 i keep 25 p.s.i. to keep an even wear pattern. otherwise it wears more in the center.

The ones I'm using are 31x10.5x15... instead of using the stock 15x7 inch wheels, I [after looking for about 6 months] got rally/factory 15x8 inchers; to give extra width, traction, and a flatter footprint. I've noticed over the years, doing similar allows a little extra air to be used without causing that hard bouncy ride, you get when using narrower wheels. Using a wider wheel, I'm able to run about 35-36lbs in mine... and they perform very well.

It's on the Sidewall of The Tires

JarJar wrote:

Draw a line across the tread with tire chalk. Drive it some and see how the line wears away. Center goes first, too much air, sides wear first too little air. Even wear means the treads flat on the road. This is how I did it back in the '80's when I used to run wide low profile tires on my van and there was no recommended pressure for a custom tire/wheel combo. BFG AT KO's on my Yukon seem to like 42 psi in them, stock size/wheels.

yep... but keep in mind that the pressure on the side of the tire is usually the MAX. recommended..

I have 8 ply truck tires that say 65 on the sidewall.... when we're towing, we might go to 50 in the front and 60 in the rear, but if we're not towing, anything over 40 or so in front or rear makes it ride like a skateboard..

Hi

Thanx a lot for all the answers - it was a great help. I?ll try the chalk trick ;-)

CU JarJar

Someone on here once said to take a piece of paper and lay it on the ground, drive over it and see if the track is the width of the tire.. The other day I was getting gas and the pavement by the pump was wet and when I got out I noticed that the full width of my tread was not wet. I lacked about 1/2 on each side.. So I said, hmm.. must have to much air....... anyway, I think it would be pretty easy to wet down your drive way a little, drive on it and see where you are.. of course you really need to start with more air then you need other wise the tire will be wet and hard to read.

Adair

This is a common misconception. The pressure printed on the sidewall is the MAX COLD pressure. Running that pressure will give you a VERY firm ride and alter the wear characteristics of the tire, possibly providing a significantly shortened tire life. That is in no way an indication of what pressure you should ACTUALLY run. I'd start with a baseline using the placard on the driver's door, then adjust up or down from there. Or, do the chalk method as another poster suggested, again starting with the pressure on the door placard as a baseline.

JarJar....

The Important message here is "Read the side wall"! The wrong value can kill you; to little and it will be driving down the road, to much and it might be at the pump when you try to put 60 psi in a tire rated at 32. Start with the value on the side or perhaps a bit less, then adjust using what ever method ( chalk, paper, rock or scissors etc.) but keep it close to the value or range on the side.

My personal thing is to lower the pressure a bit in winter to increase the amount the tire deforms at the bottom so that the snow gets flung out of the treads as the tire deforms back into shape as it comes off the road. Of course i do that being careful to not go too low so I don't find a flat tire when I come out on the really cold mornings.

JarJar wrote:

The sidewall gives MAX COLD pressure, not an opening range. Starting at the MAX pressure has to be some of the worst advice I have ever heard.

Doc

u forgot to mention that the Vehicle Weight is also a Factor..

Whem in doubt look at The Sticker on the LEFT front door..

roflmao... love the way you slipped that in, Dan..

On Wed, 08 Dec 2004 18:46:17 GMT, "Adair Winter"

Damn! that's a great idea! One of those things that you had to kind of "discover" like you did, because it just isn't something that you'd think of doing, otherwise.. (making note to self to wet down part of driveway tomorrow)

I checked mine this morning... both trucks say "max inflation" on the sidewall...

Michelin once sent me a chart covering recommended pressures in their tires. Some highlights were:

The pressure on the sidewall is maximum cold pressure.

The proper inflation pressure for any tire is going to be set according to the amount of weight being carried by that particular tire to a maximum of cold pressure shown on the sidewall. With the chart from Michelin, I weighed the front axle, divided by two (tires) and inflated according to their chart. Same for the rear wheels.

My truck comes from GM with a recommendation of 60 front and 80 rear. This is based on maximum load, properly distributed. When running without cargo, the inflation pressures don't need to be that high but it is impossible for the factory to know with what weight you have on the tires, hence they go with what would be maximums.

Cannot locate the chart right now, otherwise I'd include an example.

Michelin was the only manufacturer able to provide that information to me at that time.

Here is a short article on tire pressure.

Doug