Tire pressure for my CJ6

How can I figure out what the tire pressure should be on a 1960 CJ6 with 7.50-16LT tires? I have a digital pressure tester and I'm getting about 20psi which sounds low but the tires look very inflated.

BTW, is 16" the stock wheel size on a 1960 CJ6?

 

Thanks! And the 20psi FSM tire pressure applies even though I don't have factory size tires?

 

Funny, I was told to inflate the tires to 32psi front and rear on both the cars and the trucks when I was a kid. 10 years old in 1961. Why would the JEEP tires be a different inflation psi?

 

^This. What tires shops suggest also.

 

A jeep is a lot lighter than most trucks and cars. Also jeep tires are most likely wider.

 

A lot of discussion on this in the 1968 CJ lift spring thread.
The tire pressure on the sidewall of the tire is the maximum pressure rating at the maximum load. It has nothing to do with proper pressure for your particular vehicle. Modern vehicles have a "tire placard" that tells proper pressure for that particular vehicle using stock tire size.
Since that doesn't apply here follow the procedure outlined in that other thread, assuming you are not running ndt's. Those are a different animal.

 

Tire technology has changed just a tad since 1961.
Not to mention vehicle weight, load characteristics, tire construction, the list goes on and on and on. And that was bogus in 1961 anyway m

 

I think that optimum tire inflation varies for each vehicle. If you are running LT tires they are designed for a huge range of vehicle weights. These are the same LT tires, maybe, that I run on my F350 and inflate to 65 - 80 lbs.

For a lightweight vehicle like a Jeep you should experiment a bit and pay particular attention to the tire contact surface. Too much inflation and you're looking at a tire where the center crown contacts the road more that the side portions of the the tires. Too little inflation and you are over stressing the tires,

Load the vehicle to operating weight, inflate the tires to max indicated, then go down by 5 PSI per step, checking for contact surface. When the contact surface is flat (even between inner and outer contact profiles) you are close.

 

Do the chalk test. The chalktest is one easy way to determine what psi is best for tread wear. If you're not familiar with this, color the tread area with chalk. Drive a couple hundred yards and look at how the chalk wore off. More wear in the middle = too much psi. More wear on the outside edges = not enough psi.

 

What he said. Works every time.

 

What I have noticed with my '60 is if I let the pressure down to what you all say to run, like 28 psi for a high and about 20 psi for a low range, I get a death wobble outa the front end. If I run them at 35 PSI which is still lower than the manufacturers recommended maximum, I don't get a death wobble. And that is what I go by.

 

Then you have other issues that need attention. Not enough positive caster, something worn, something out of adjustment, etc. the higher tire pressure is simply masking the problem.

 

For what it is worth, I have 31" 10.50's on my CJ-5 and I have found that 25 psig is the best. I think you need to find out what works best for your vehicle and the type of driving you do. Remember, when our Jeeps were made, radials were not available either. I used to sell tires part-time when I was in the military, and when radials came out, people came in and tell me they wanted a set of those "those new radio tires". I was always tempted to ask if they wanted AM or FM.