just wondering what tire pressure I am supposed to go by. this is for a 1999 chevy cavalier. the door jam says 30 psi front and back,the tires themselves have 44 psi max on them.I am going for max tire life and gas mileage here. thanks for any insight.....Ben

 

I had a '98 caviler and I ran 35psi.

 

I'd go with 32psi, no need to go near the max pressure on a cavalier.

 

i would go no more than 32

 

Don't go by what's on the tire. The door sticker is what the manufacturer recommends as the 'correct' tire pressure. I usually use that as a starting point. On my wifes car (lumina) it's spot on. Gets good mileage, no unusual wear, no screeching around corners...On my Explorer, the door sticker isn't even close. Ford Says 26 psi. With the tires at that pressure, they look flat, noisy as heck around corners, wear at the edges and a very mushy ride. I usually run 32-35 in my Explorer and all of those problems go away.

Matt

 

32 psi is a good pressure. Alot of times the door sticker is the best to go on, but that is usually tested on the tire that come stock with the vehicle.

 

The real way to do it for max tire life is to put in the PSI of pressure that gives even tread wear based on the load of the tire.

As the load of the tire increases, the psi needs to increase accordingly, and vise versa. If you're tires were rated for 2000 lbs at 44psi, and you only had 1500 lbs on them, then you don't run 44psi or you'll wear out the center of the tire quicker than the outer edges as it's overinflated. You'd only run 44psi if there were 2000lbs on the tire.

Also, the PSI on the door jam sticker is for the original tire. If you change tire brands/styles, the psi changes accordingly.

I will use a piece of chalk and mark a 1" line accross the tread of the tires, drive it on flat pavement so they roll over a couple times, and check how the chalk was scuffed off. If it scuffed off more in the middle than the outsides - pressure too high, and vice versa. I'll play with the PSI until the chalk scrubs off evenly. It's also important to remember that if, say I load my truck up - I've gotta add pressure to compensate for the weight or the tire will be underinflated. Underinflated tires run the risk of overheating and blowing out.

That's getting pretty into it, as the others have said - 32 psi or so will probably do the trick.

 

That is a GREAT idea!

 

I've done a lot of work with motorcycle tires in the past. The following is what we have recommended to our motorcycle customers but works for auto tires as well.

Use 32-34 as a start, not what it says on the door pillar which is only for OEM tires. After a 20 mile drive or so, check the pressure again. When properly inflated they should increase in pressure about 10% i.e. if starting at 32 psi the warm pressure should be at about 35 psi. If they are higher than 35 it means they are running to warm and the starting pressure is to low. Conversely if they are running lower than 35 psi they are running to cool and the starting pressure was to high. I've been doing this on my auto's for a while and found the tire wear is nice and even and I'm getting the expected life out of them.

 

That makes a lot of sense. Hadn't heard of that before....

The pressure on the tire is usually the Maximum for that tire. If the load rating for the tire is 1500lbs and you have a 6000lb vehicle that's the pressure you need to run. However the tires selected for a given vehicle should have a much greater margin of safety than that..... and therefore lower pressures are called for.

Good posts in this thread.