Marca

What pressure are you guys running for street use on your 37's. Ive been told 36 is the way to go, but the tire shops always fill them to around 44.

jedg

Both of those pressures sound too high compared to what most folks run (I run 28 psi in my KO2s). But, the pressure will depend on the weight of your vehicle, the brand of tire, and the load rating of the tire. Your best bet is to conduct a chalk test to determine the best pressure for your vehicle. Do a search on YouTube for 'Tire Chalk Test' and you will find several videos that will walk you through this.

resharp001

Agree with Jedg above. There is no "one size fits all" when it comes to tire pressure, but those are way too high. I run my 37" Nitto TGs around 27/28 cold, heating up to 29/30 when hot, but mine go up/down so much that I've run 25/26 when cold too with no cares. Whatever you choose, you're always going to have the trade off of drag/fuel economy vs. even wear/life of tire.

dmalpas

Falken Wild Peaks 35x12.50 with a 121 load rating. [These suckers can each support 3,200 pounds at max psi, which is only a 1,000 or so less than the weight on all four wheels]

I did the chalk test on all four tires and even wear indicates 20.5 pounds. Never had 35's before it sounds low, but if the chalk test is accurate what I think is not relevant.
Anyone think is reasonable. I should hate to trash a new set of tires.

resharp001

Although I think the chalk test is best to really determine when the full tire is making contact, I think my experience has always been the PSI that dictates is indeed typically really low. That is where I start thinking that even though the PSI might be "correct" in terms of pavement contact, there does come a point that you're creating much more drag and drawing on fuel economy in order for more even wear. I think it's just one of those things there's no REAL right or wrong, you just have to find some middle ground you're comfortable with. Typically, I'd think people are running 35s in the 28-32psi range (cold), with many not knowing better and probably still way. 20 seems too low to me, regardless of chalk test. I probably even run my 37s a little high, but I make up for it tearing up the outter lugs on the rocks.

dmalpas

Fuel economy? In a Jeep? It could not get much worse. But it is a special purpose vehicle.
Most of the tire revolutions on this Jeep are towing it. Most of the rest are crawling on rocks, so MPG is not as much of a concern as trashing a set of tires.

I had them set to 28 when installed and around town, it was not a bad ride, slightly stiff. I am going to drive them at 20 for a week or so and see if they feel "squishy"

Would love to hear from someone running the 35 Falken's and what psi they are using and how they are wearing. I know one man who has them and he runs 30psi when towing and 15 around town. I can't figure out why he has such a difference.

resharp001

Oh, it can, and does.

If you have that on a 17" wheel, looks like it's an "E" rated tire per their website. That is a damn stiff sidewall, specially for a 35, so I can see it testing out at 20 psi with chalk.

jedg

I guess I'm just going to follow resharp around and say 'what he said'... yeah, an E rated tire has very stiff side walls... heck, I run E rated tires on my 2500HD to tow with... they are built to take 75-80 psi and a heavy load, so getting full contact on a 'relatively' light jeep (compared to a 2500HD with a goodneck and 10,000lbs) probably does get you to 20 psi.. I think you're going to want more psi or risk cupping the center of those tires.

hivoltagedriver

I ran my "E" rated Dick Cepek 35s at 28-30psi, and my new Pro Comp MT2 40s that are "C" rated at 25psi on the street. 60k miles on the 35s and still decent tread left (rotated every oil change). We'll see how these 40s do.