I just got this Jeep, and it came with brand new tires. They're Goodyear Wrangler SilentArmor "Pro-Grade", 225/75R16. I was making a nice 180-mile trip and I noticed whilst driving that, at 55 miles per hour, the truck vibrated like a Magic Fingers bed. When I got to my destination, I got the tires balanced, which made no difference. I also noticed that they were wearing on the edges (both inside and outside) so, on a whim, I figured I'd check the pressure. They were all inflated to 35 psi... which I would normally write off as normal, except that it says right on the tire to inflate to 80 psi.

Eighty frikkin' psi!

Okay, so it's kind of obvious that these tires were meant for, like, a dump truck rather than a fifteen pound XJ, and the idea of inflating the tires to maximum seemed preposterous (hitting a pothole would launch me to the moon), but I figured I should do something, particularly because they were wearing along the edges which is a hallmark sign of low pressure. I chickened out on the full 80, though, and inflated them to 65 psi... which took care of my vibration problem entirely, though they're so stiff now I can't run over a paperclip without bouncing out of the seat.

So I guess my question here is... what pressure do you think I should run these things at? I imagine I'll experiment and figure something out, but it's obvious that 35 psi isn't enough, and 65 seems a little bit, er, too much. Or should I just take these off and throw on some cheapie Futura Scramblers or something (which rode pretty nice on my old Jeep, and my S10 Blazer seemed to like way back when)? I almost don't want to get rid of them just because they're brand new and apparently fairly expensive... but daaaang.

AJ

 

Well first off the PSI rating on the tire is a max PSI rating. Though a max rating of 80PSI means it's a load range E tire, definitely a bit stiff for a little XJ. Most people use C load range tires on an XJ. I think you're gonna be hard-pressed to get a good ride and even tread wear out of those tires,

 

x2

 

You're absolutely right, they're totally not for this truck at all.

After messing around with it last night, I found a pretty good ride with the front inflated to 60psi and the rear at 50. No vibration and as smooth a ride as leaf springs can give you.

Thanks!

 

This is exactly what I was going to recommend. Just play with the pressure until you can find a decent ride. At least until you pick up some new tires.