I'm new to the Jeep world. I bought a 2013 JKU Rubicon and it had mud tires on that were cupped and rough as heck. I got those changed out with 315/75/16 BFG TKA02's. The ride and noise improved a ton. I'm now trying to find ways to get as much steering/tracking stability as I can out of this set up. There is a black mountain outfitters lift on the Jeep, but as I am new and I didn't set the Jeep up, I'm not exactly sure what I have goin on underneath me. I love the Jeep and I absolutely understand that its a Jeep and its gonna wander a bit. I'm not looking for a Cadillac ride, I'm just looking for ways to improve what I have to the best degree possible. Any help for a newbie will be greatly appreciated.

Thanks

 

I run 35psi & my tires are LT315/70/R17. How high is your lift? I'm @4.5in my 2011 Jk unlimited dissent wander at all. What does your lift look like? Can you post some pictures?

 

That is a really high pressure for that size tire. Chalk test is best, but 28-32 PSI seems to be the correct range for most 315 and 35s. Keep in mind that once you start moving, pressure increase 3-4 psi.

OP, in terms of the tracking issue, that could be any number of items. If your lift does not include any type of adjustment for caster (probably doesn't) that is most likely the cause of the wandering issue. Think of the front fork on a bicycle and how they are angled forward. Imagine if the fork was straight up and down - handling would be terrible, it would be twitchy and would wander. Same thing for your Jeep. The part the steering knuckle attaches to (the inner C - easy to find as it is the part at the end of the axle shaped like a C), is at an angle. That measurement in degrees is your caster. Because the upper and lower control arms are different lengths, as you lift the Jeep, the axle rotates forward and reduces your caster (made the fork on you bike closer to perpendicular to the ground). The solution is either adjustable lower control arms or geo brackets. The brackets work and are about 1/3 the price. People who want to dial in and/or offroad a lot, tend to get the arms instead.

After that, you have to start looking into the steering parts to see what is worn out. Could be ball joints, tie rod ends, drag link ends, etc.

 

As already said 35psi is way too high for a 315. Chalk test is the best method for determining as everyone's JK weighs a little different. I'm moderately weighted (bumpers, winch, gear) and my pressure is at 28.

 

I believe that this Jeep was customized by Collins Bros in Wiley Texas. From their website and what I'm seeing under the jeep, I think its a 3 inch lift. When I checked their catalog listings for the lifts they sell, the 3 inch lift is pretty basic. I just lowered my PSI to 35. I put a new set of BFG TK02's a week ago and discovered that Discount tire had my pressure at 42!!! From the sounds of it I may need to go lower. I also need to do a chalk test this week it seems.

 

I just read about how to do a correct chalk test. I'll get it done this week and see what its showing.

Thanks for the advice.

 

Your explanation of caster and the difference it makes really helped. I looked up a lot of information on the brackets and I think that's a damn cheap way to possibly get a lot of improvement. I appreciate the help. I'm new at the Jeep thing and I've got a ton to learn.


Thanks

 

It is ... Another option is to run adjustable upper arms. They just need to adjust shorter then stock like MC, Synergy. Uppers are a little cheaper and easy to install.