Just put a Rock Krawler lift kit on my JKR. Was finding it too stiff and jittery with their RRD shocks too. Was running 30/28 PSI and then 28/27 PSI. RK says I should be running around 20 PSI on pavement. While I think that these guys really know their stuff in general, does this strike anyone as being too low? Do I really need to run such low PSI? I'll run ~10 PSI offroad but 20 PSI on pavement goes against everything I have heard or read...don't want to blow a tire or something.

 

Did you add Lca? If not did you add cam bolts? Again if not, you caster is out causing flighty steering. Add lca that are adjustable.

 

I run 24 on the street with my mud grapplers. Just did a 500+ mile road trip.
If I run 30 I can tell a difference in the ride, gets a bit harsh.
My wear pattern looks perfect at 24 also.
Depends on tire size also. My buddy runs 20psi on his 40 mud grapplers on street.

 

I run these tires in a 35" with 29 psi on the street with no problems and a comfortable ride.

I agree with your opinion that 20 psi might be a tad low.

How old and how many miles do you have on the tires?

 

I used the RK X factor kit so all adjustable control arms. The kits is pretty new, as are the 35" C-rated MTR Kevlar tires- maybe 700-800 miles on them. Jeep is at the shop still, and I'll try the chalk test as soon as I get it back.

 

Yeah....welcome to the world of wrangler. I run 23lbs in the street; I can go higher, but it chatters more and more with each extra pound of pressure.

 

I have d rated 37s and run those at 25 and it seems to be a good balance. At 20 they definatly ride smoother but handling feels spongy. And 30 handling is firmer but I can feel the little bumps. Tire wear seems great.
Good luck

 

I run 25psi in my 37 inch MTrs on the road and the feel great. Anything over 30 and you can def feel the difference.

 

Do a chalk test. You want a flat contact patch with the road, but the sidewalls should remain relatively flat. If they are sagging, you need more air.

 

I come from a lengthy tire shop background and I was very skeptical about running the tires at low pressure as you are. After a lot of experimentation I found that 24 to 26 PSI is best for D and E rated tires on a JK. Any more than that and you will notice a crown in the middle of the tread leading to flightier steering and the centers wearing out before the edges. One thing you never want to do though is adjust tire pressure to compensate for ride quality. This can mask issues and lead to tire failure. I have been running 25 PSI on my 38's for 3 years and have great wear patterns and exceptional tread life. I also run the rig at 80+ mph regularly and don't get the loose feel caused by a distorting tire (caused by low air pressure). Every tire is a bit different but if you stay in the upper to mid 20's for PSI, I think you'll be happy with the results.