actually most michilen tires call for 50-80 psi and a number of of manufacturers are starting to want you to be in that range. My Good Year Duratrac's put MAX psi at 80 and from the factory they are recommended to be placed at 35 - 45 psi. As is most manufacturer recommendations for that are a little soft. As for the OP... tune up is a big one... make sure ALL fluids are at the proper level and in good conditions. Those nice meaty tires have to go as well... stock tire size will help you out. Look for anything that is hanging off the vehicle that is not needed and remove. After market lights and sound systems may be nice but more then likely you don't need them. Clean the inside of your vehicle out! I just did and weighed all the crap that I had in there and it was over 100# in there! That was all unneeded weight.

Also allowing your engine to breath and exhaust better helps but a new o2 sensor helps more.

 

DO NOT leave your psi over 5-10 under pressure of what the tire says. What your door says is only for the factory tires, if you have any aftermarket tires, go with 1-2 psi below what the tire says. If your rock crawling, then you just have to go with what u feel is safe.

 

Really people? Go with what the door jam says. The side wall IS NOT THE RECOMENDED PRESSURE!

 

I've blown tires because of reading the door jam!

 

My 97 ZJ 4.0 was getting about 12.2 mpg with my VIC telling me "Coolant senser bad". After I changed it I'm getting about 16 mpg on the road so I'm not complaining. After all, it is a jeep!

If you want good mileage, buy a Prius!!!

 

I disagree. These things came stock with practically a passenger car tire. Most any aftermarket tire is going to be intended for a light truck that is heavier than our Jeeps, even the chubby WJ. Over-inflation will cause not only a terrible ride but also bad tire wear, for perhaps 1 mpg gain? Not worth it. Learned that one the hard way.

 

You're right about overinftation, but its of what the tire says. I've always listened to the tire's psi and never had bad tread wear. I do agree that a little bit of underinflation isn't bad and causes a little softer ride, but better shocks will soften the ride too.

 

For clarification purposes, when I say over-inflation I was talking about for that particular vehicle (door sticker) and not over inflating the tire (sidewall), which is obviously not smart. But now that I'm thinking about it on smaller cars I've owned, I've always gone with the tire instead of the door, so I guess it's 6 in one and a half dozen in the other.

I'll just wrap my thoughts by saying that for me personally, on my WJ with aftermarket tires, I prefer the factory recommended psi as opposed to the sidewall psi.

 

Also, look at the Ford Explorer recall. I don't remember how long ago it was but they were rolling over because they filled to the door psi and not the tire psi.

 

No, that was due to faulty Firestone tires.

 

The cause of the rollovers was still from underinflation tho.

 

Gentlemen! (where?) I believe 32-35 psi will work with just about ANY tire short of heavy equipment trucks and aircraft. I've only lost one tire in my life and that was because of a sidewall cut. 40 psi for road racing and 26 for rock crawling works for me.

 

Gentlemen! (where?) I believe 32-35 psi will work with just about ANY tire......<<<

Has always worked for me.

My mom was complaining to me about her mileage, checked her tires and they were 12-15 PSI each...

 

The Ford tire problems were caused by the factory (Ford) trying to make the ride more comfortable for street use. They should have not done this. It was not the fault of Firestone, because when the problems started Firestone stated their tires should not have been run with the reduced pressure which caused extreme heating and rollover problems.

IME, Firestones are great for traction, not long wear.
Goodyears are long wearing but are too hard for good traction.
Goodrichs are a good compromise with both good traction and decent wear.

 

How does the door jam know what tires you have? I wonder if manufacture techniques and or technology has changed since my 96 GC was sent down the line. I looked it up and yes they have. My guess is the tires that came from the factory in 96 arent even manufactured any longer.

The door jam is only for original equipment tires.

Thats being real