I usually stick to 36psi cold. I used to run at 33psi, but a little firmer makes the drive better IMO. It doesn't seem to track the road grooves as much.


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Tire pressure as stated on the door sticker is the optimum pressure COLD for the particular vehicle. Of course the pressure naturally increases with heat & normal driving.

The pressure rating on the sidewall is simply the maximum inflation pressure. This isn't necessarily the best pressure for optimum tire patch on the road, wear, durability, etc. I adjust mine for the seasonal temps. I figure the engineers are a bit smarter than I am.

 

I realize the stated amount on the door would be recommended cold PSI, and what's on the tire is max rating, etc. But given the vehicle came from factory with nitrogen filled tires, and nitrogen isn't supposed to change PSI as inert...as I understand it...then it is strange to list a factory PSI for cold tires. What would the optimum PSI be then for tires up to temperature? And then shouldn't that really be the suggested PSI given nitrogen filled? I'm just saying it doesn't make sense what the factory is listing. And then of course my tires are at 40 PSI from factory...which would be excessively high if they suggest 33. I haven't checked pressures with a good tire gauge yet to confirm it matches what the computer is telling me. But obviously is it's accurate, then I'll drop the pressure down to 35 or 36 PSI...which would roughly be normal tire operating PSI at temperature, with tires recommended for 33 PSI cold, if filled just with air...not nitrogen.

 

It's true the nitrogen doesn't fluctuate quite as much but unfortunately in my town, there is no nitrogen so I simply use air for convenience. I've found that the evic tire pressure gauge is calibrated correctly & that tire pressure under normal operating increases 2-3 lbs.

 

If I remember correctly tire pressure changes 1 PSI for each 10 degrees of temperature change. The atmosphere is already 80 percent nitrogen so I've never really seen the point of going out of my way for 100%.
In theory you want to run the pressure as close to the tire max as you can to maximize fuel mileage especially since an increase of 2 mpg is like a 15% increase for us This is provided you don't see any abnormal tread wear and you're ok with the ride quality and tracking.

 

i run my wk1 at 32psi cold

 

WOW, I woulda never thought to go that low, I gotta try it out and see. I'm around 37-38

 

I went thru the nitrogen phase as well, too much trouble for the following reason;

In order to fill them with nitrogen, it only makes sense you'd want to get rid of the air that's already in the tire. Even at 0 psi, the tire chamber is full of air (14.7 psi's worth @ sea level to be exact). Being an HVAC contractor, I made use of a vacuum pump to remove as much air as possible. Below were the results










No, the tires weren't damaged in any way. But I don't think it's a good idea anyways. I did this mostly for kicks & it wore off quick enuf. Popped one tire off the bead as well, so there's a point where you really shouldn't be pulling anymore air out.

 

So now that we're talking about tire pressures, how many here who have had the Good Year tires fail were running over inflated tires? I'm just asking the question because I have run the Good Years from day 1 with no problems. I actually quite like them. Anyone?

 

0n my 07 i ran GY RUN FLATS from day 1 with the air pressure set at 36 cold and at the track 40 front hot and 36 rear hot and they hooked. The Pirelli 3 season are diff as the rubber compond is 220 and is softer than the 260 gy run flats and in testing on 1 of our members jeep the best airpressure is between 33 & 36 hot depending on the track prep. It seems that 36 cold is the best all around pressure for longevity on these runflats.