Tire pressure

I ran 4-5 without beadlocks, only broke a bead one time. M/T Classic 2's and 37's.

I wouldn't worry as much about the contact patch as I would about the sidewall strength in a slide. If you drop it too far on the street, just to get a good contact patch, you may weaken your sidewall strength to the point of losing a bead should you become involved in a lateral skid. If you break the bead at that point, you'll likely dig the rim in and flip er over.

that seems really low...perhaps the colder weather and new rubber is throwing the "test" off? give it a couple heat cycles and try it to verify?

I ran my old style MTRs on the street at 18-20lbs. They were the smoothest that way and virtually eliminated any bump steer and helped a lot when chasing death wobble.

Quote from 2000sahara

and virtually eliminated any bump steer

What does tire pressure have to do with bump steer?

I run my MTR's on my JK at 25 psi and get even wear but it might be a little heavier than your TJ. I think MellowYellow is right about the cold and new rubber. I'd give it some time to break in the sidewalls a bit.

Quote from KnoxRents

What does tire pressure have to do with bump steer?

I run my MTR's on my JK at 25 psi and get even wear but it might be a little heavier than your TJ. I think MellowYellow is right about the cold and new rubber. I'd give it some time to break in the sidewalls a bit.

Perhaps I'm using the wrong term. Here's what I'm saying....
Blow those tires up to 35lbs and you can feel every single bump through the seat of you pants and through the wheel. Often the steering wheel will feel like it's trying to rip from your hands. Drop the tire pressure down to 18psi and you will notice a much softer ride and it seems, the give in the sidewall will soften the "rip from your hands" jolt you might otherwise get from a lifted jeep with piss poor steering/suspension design.
Get it?

Quote from 2000sahara

Perhaps I'm using the wrong term. Here's what I'm saying....
Blow those tires up to 35lbs and you can feel every single bump through the seat of you pants and through the wheel. Often the steering wheel will feel like it's trying to rip from your hands. Drop the tire pressure down to 18psi and you will notice a much softer ride and it seems, the give in the sidewall will soften the "rip from your hands" jolt you might otherwise get from a lifted jeep with piss poor steering/suspension design.
Get it?

Yeah...now I do. You mean that the softer tires hide the bump steer caused by having a drag-link and track bar out of parallel or one way longer than the other....not that the hard tires are the cause of it.

Yeah Whatever.... Next time I will draw you a picture...

You only have 8 inch wide rims. You need a 10 inch wide rim to get a good contact patch with a 35x12.50 Its really cold, once it warms up you are probably going to but it back up to about 25 psi. Wheel it and you will help soften up the sidewalls.

I have 37"x12.50x17R MTRs on the street jeep. I run them at about 20psi. I get good wear and contact . I have 10" wide wheels FYI.

18 psi - 22 psi seemed to be the best spot for most tires I ever ran on the Jeep due its extremely light weight (compared to the tire rating). Best ride and wear, just be sure to rotate regularly and watch the wear pattern...

This is very interesting. I wonder how much softer the ride would be if I lowered the pressure in my tires... Right now I'm running at about 32 PSI. I just figured the rough ride was all due to the leaf springs. I will definitely have to give this a try.

The 35/12.50/15 MT/R has .5" more tread width, This could cause the difference in contact patch versus your 33". Goodyear recommends at least a 8.5" wide wheel for the 35" (33" too actually) Should be fine at 18-25 psi.

Quote from Erock

So i dropped to 20 psi, helped a bit, still dont have full contact, but im going to see if it will soften up a bit like that. i did drive it to work today (35 miles) and it def was not too soft or poor handling, so im happy with it for now. i dont think i really want to go below 20.

This is really the right method. You want a slight bulge in the sidewall since these are not being driven like race cars (I hope). Just watch/feel for excessive sidewall rollover. Huge difference in steering feel for the better at 18 psi versus 32 in my experience. I always forgot to air-down after having a shop mount new tires. Always remembered after the drive home though. Lol. Also always ran 8" wide wheels for 12.50 tires, and 9" on my 13.50's, never had issues. IMHO 10" wheels just look stupid and are that much more exposed to rocks and such.

Also interesting - http://forum.ih8mud.com/tire-w…rison-clearance-loss.html

http://www.jeepfan.com/tech/air-down-basics/

While chasing down a steering issue (hard pull to P-side), I checked my tires and discovered the following:

FD: 30 PSI FP: 18 PSI :o

RD: 28 PSI RP: 28 PSI

I think the FP tire was due to the ridiculous amount of potholes in our neighborhood burping out a little air here and there. I'm keeping an eye out though in case I have a slow leak though visually I didn't see any punctures. So, I went ahead and aired down the 3 tires to 22 PSI and then filled the FP tire up to 22 PSI. After a few days of driving on them, it feels like the lower PSI is actually allowing the tires to absorp a lot of the smaller bumps and stuff on the road. Having leaf springs isn't ever going to feel like riding in a vehicle with coil springs but I'll take what I can get.