tire/pressure ?

ok, I feel pretty stupid asking this (I should already know the answer to this).

I've got a 1975 CJ 5. It has a 4" suspension lift (very stiff) and 31" MT Baja Claws. 31x11.50x15.

What tire pressure should I be running on the asphalt? The Jeep service manual recommends 20F/24R for speeds less than 50 MPH and 35F/35R for speeds in excess of 50 MPH. But this is for 31" F78 tires (I have no idea what these are). The tires are currently inflated to 25 PSI at all four corners. They look and ride pretty good to me, but I wanted to get opinions from you guys (and gals). I'm afraid to run them up to 32 (like my other vehicles) or higher. With the 4" suspension lift, the Jeep already rides like a pogo stick R) . I don't want to make it any worse, but I don't want to hose the tires from under inflation or put my self in any more danger while driving the Jeep (a la Ford Explorer). It's already hard enough to drive with the stiff suspension, short wheel base and a steering box in need of a rebuild. Every ride is an adventure to say the least.

HELP! And thanks in advance for the advice.

 

Mine is an 80 CJ-5 with about 1.5" of suspension lift and am running an old set of 31x11.50 muds on 15x10 rims. I run 20 PSI on the highway, around 14 on the dirt and as low as 12 on soft beach sand. I've never popped a bead and am getting good flat tread wear. Highway ride with the 20 psi is very decent. Must be your suspension.

 

the tire manufacturers recommendations should be on the side of the tire for max inflation
it is not uncommon to run slightly lower pressures to obtain better ride characteristics
lower pressures may cause your tires to wear out faster
might also feel mushy when cornering at higher speeds
I agree with 80cj, probably your suspension being very stiff

 

Oh, it is definitely the suspension. I just don't want to make it worse by inflating the tires too much.

The manufacturer's recommendation for maximum inflation pressure printed on the side is 50PSI The MT website says to start at about 70% of that, but that would put me at 35 psi. I think this is too high.

Sparky, I like that idea. I figure I'll wind up pretty close to what I already have, but I'll give that a shot and see what happens.

 

I did the same as sparky says and i found that about 24 to 28 works for my Jeep.
While off roading on sandy trials I run about 12 PSI, at Silver Lake Sand Dunes I run about 4 in the front and 3 in the rear, while off roading in mud I run about 12 to 15 PSI.