i KNOW THIS IS KIND OF A DUMBASS QUESTION BUT I WAS RUNNING AROUND 35 POUNDS OF AIR IN MY 265-75-16'S I READ THE SIDEWALL AND IT MAXES AT 60 AFTER FILLING THE TIRES TO AROUND 55 LBS I NOTICED MY GAS MILEAGE IMPROVED BUT THE RIDE QUALITY SUFFERED ANY INPUT ABOUT PROPER INFLATION? THANKS IN ADVANCE

 

Tires are designed for a wide range of vehicles, the pressure on the sidewall is the MAXIMUM pressure for that tire. Not the designated pressure for the Jeep.

Your tire pressure is defined by your vehicle weight. 55 is way, way, way to much. I never had that size tire, but around 30 is more ballpark.

 

That ain't a dumb question. The reason the tire says 60 is because it's probably a load range D...it could be an E, but I wouldn't think so. If you want to be safe, run what your Jeep says in the door jamb, which I believe will be 35. The max air pressure is relative to how much load the tire has. I am sure you are nowhere near the max for one tire at 60 PSI, much less 35.

 

Thanks guys ill drop it back down im just kinda wondering about the difference in fuel eco im only getting around 14 mpgs now and thats an improvement

 

I run 37 in a Sahara Unlimited with the 255/70R18 stock. That way, by time I check them the next month, they are just passing 35 (spec).

On our other Jeeps (TJ and a Grand Cherokee), I'll fill 1 pound over the door sticker. That way, they're over for half the month, and about right on for the second half of the month.

I have not found any wear or ride problems at 37 on the JK.

I think this gives me the best milage, without going much over the door sticker spec.

Offroad I would air down of course.

I use a higher quality dial guage (actually Jeep sent me a nice once years ago during some promotion.) The stick guages are not very accurate in my opinion.

The only tires I run at Maximum are Trailer tires... on there you want to prevent overheating at all costs, and you generally don't care about the 'ride' of the trailer.

 

I run 35 in the winter and 40 in the summer in mine
265/75/16 toyo at

 

Your modest boost in fuel economy will be offset by much faster tire wear at higher pressure. If you want to find out what you need, do the chalk test on the tread. Simply mark chalk across the tread on the tires and go a few revolutions. If the chalk wears in the center first, you're over-inflated, if it wears on the edges first, you're under-inflated. Even wear means you're good. THere are other variables such as alignment to consider as well. You can also do a similar test by driving through some water and then look at the tread imprint on dry pavement and see if it is even, etc.

 

Be careful with too much air in the trailer tire. I was pulling a Trailblazer Off Road Camper over Engineer Pass in Co. at about 2 mph, hit a rock and flipped the trailer because of 32 lbs air in the tires-hit the rock just right and it bounced like a basketball took it right off the hitch and ripped off both safty chains-all at a 2mph crawl-a lot of air with not much weight = big bounce! Now I run 20 lbs or less on the trailer depending on the terrain.

 

I was running max psi on my tires. Not the tire max, but the Jeep sticker max. But on some dirt roads the washboard effect felt like it was vibrating my Jeep apart.

I backed off a little and that helped soften the ride somewhat.

First I've heard of the chalk test. I'll use it to see what's what on dry pavement at the psi I'm running now

 

Tires on a car are the absolute definition of "compromise".

Think about it. If you want perfect gas mileage, then friction is your enemy. However, if you want to accelerate or turn then friction is your friend. To get the best dry performance, a slick is needed, to get best wet performance, a tread is required. A tire is nothing more than a compromise of what you need at that very moment in time. It'll never be perfect all the time.

Same thing goes for the air pressure inside. Ideally the tire would automatically inflate and deflate as required and never suffer adverse effects from over/under inflation. But if that's the case in the world you live in then please let me into it too!