I currently have a jku running 3.5 lift, 40s, Dana ultimate 60s, redhead steering box with psc hydro assist. Right now I’m on metalcloak mid arms mounted to the stock location on the frame. I foresee changing some of this in the future. My plans aren’t set, but I’m thinking long arms, 5.5-6 inches of lift, and likely coil overs. And if I do those, I will probably do something stupidly impractical like 18 or 20 inch. And of course, why stop at 40s when I can get 42s or 44s? The wisdom of that is a conversation for another day.

my current issue is that even with the 60s and 3.5 backspace, my tires rub the frame on the corner where the diagonal section starts. This prevents me from getting all the steering lock available, and leads to 19 point turns on tighter trails. If I were to move the front axle forward 4-6 inches, I’d get another 3-5” of frame clearance. I’d also get better approach angle and anti squat/dive from moving my cog back.

I don’t really want to go wider for two reasons- 1, i already have a hell of a scrub radius, and 2, I already find myself rubbing both tires and fenders trying to pass between trees on certain trails. Increased lift might help by raising the point in the arc of the tire that is near the frame, but that only works unstuffed.

so I realize I’m in for custom control arms, coil over mounts, a new drive shaft, coil overs (unless this could be done by moving the spring perches and shock mounts), and some modification of my steering.

first question, how far forward can I move the steering box? I assume the steering shaft angle and location are fixed, so lengthening the shaft will lower the position of the box.

could i get/make a longer pitman arm?

it doesn’t look like moving the track bar, tierod, and axle end of the drag link forward with the axle is going to create any new clearance issues, but I’m concerned about the pitman arm and steering box. What are they likely to hit?

this seems only moderately more complicated than doing a regular coil over setup in front. Am I missing anything?

im ok trimming my grill or fenders/hood if I need more room in the front. I’d like to avoid cutting the frame.

 

Steering angle is not an issue as there are u joints on both ends of the steering shaft. You will have to extend the shaft, not a big deal if you can fabricate. You can move the box forward to the radiator, you can also replace the the radiator with a shorter one to gain clearance. this will also let you have more up clearance if you want to notch the frame. I moved my box worth forward and up so I have more stuff on the front. Drilling the frame sucks as it eats drill bit and you need to install new tubes thru the frame to bolt too.

 

Yeah, I saw your thread. I want to go further than you did. That’s why I’m wondering about the clearance issues.

any reason I can’t keep a 5 link set up with this? I see most people changing to a 4 or 3 link with coilovers, but it seems to me like the gains are modest over a long arm 5 link, but the extra cost isn’t.

 

Also, any issue with moving the sway bar or shortening the arms?

 

I run a 5 link front. I am not even sure how much my front is stretched but I am as far as I can go. For reference my front bolts on the box are 29" from the firewall

 

Hi Dirtman (and everyone else). Need to pick your brain again.

I found someone that can get me control arms that are about 1-1.5” longer. Not what I had originally contemplated, but without going coilovers or serious frame mods (complicated by the crumple zone section almost immediately ahead of the spring cups), this seems like potentially the best bang for the buck. My thinking, which I’m hoping to confirm or deny, is that to go 1-1.5 forward, I may need to extend the steering shaft, get a longer drive shaft, and possibly move the track bar mount at one or both ends. I’m hoping to get away without modifying the shock mounts or spring perches.

i currently have a 3.5 lift (may grow later). I’m thinking that the 1-1.5 inch forward deflection is not going to substantially change the angles or cause an unacceptable misalignment on the springs, but i’ll admit I’m just guessing. I have to check for clearance issues, but assuming there are none, is this small forward tilt at ride height going to be an issue?

assuming it is, is the solution as simple as something like the metalcloak rear spring alignment corrector/retainer?

again making some educated guesses, but it seems like moving the top of the spring and keeping the bottom over the axle is the appropriate method (though if the arms were stronger, it would be an interesting idea to mount the springs and shocks on the arms, allowing axle movement to exceed shock length, but then we’re talking about something different than a normal 5 link). My control arms are slightly angled down at ride height, so the bottom of the springs would be farthest forward of the top under an inch or so of compression. It might make the spring and damping rates slightly less effective based on the additional angle, but after that the spring would return to near vertical. I’m only a casual student of suspension design, but I’m thinking that at ride height or under extension or all but the first inch or two of compression, there’s not going to be a dramatic effect on handling.

any thoughts are welcome.

 

easiest thing would be to relocate the axle coil perches so your coils are lined up right, 1-1.5" will have a very noticeable bow in the coils. Longer control arms are nothing special and are easy to fabricate. A local driveline shop can extend your existing drive shaft. I don't think you are going to gain much from moving the axle 1.5"

I don't see the clearance room too mount coil overs on the front arms and there are also other factors about running trailing arms.

Stretching your wheel base will make your turn radius worse, just to let you know.

 

Thanks Dirtman. I really appreciate your knowledge and experience and willingness to share. People like you are what keep these forums worthwhile.

ill try to take a picture of where my tires are hitting the frame and post it tomorrow.

im wrestling with the law of diminishing returns. I could just bite the bullet and go with a custom coil over setup, which would let me get an inch or so more lift, which would let me use the metalcloak drop brackets, which would help me with my dive and squat, and then I could put the front axle wherever I want, but I’m looking at an easy $5k, and I don’t know that the on or off road improvements are really going to justify the cost. I’d really love to be able to adjust my preload and damping for highway use and have a softer setting for off road, but is it worth the cost of a decent TJ?

 

Thats the question you have to answer. When I see people ask about UD60's I try and turn them away as they are not wide enough for 40's, They are really ideal for a 37x12.5 tire. When you go t a 40x13.5 tire you have to be ready to chop the sit out of it or go wide. Most don't realize this and think they can just throw on 40's with 4.5" BS wheels. I remember the tree runs when I lived in the midwest and had to really watch the trail, out here it is nice to be wide for the stability and we don't do a lot of tree runs as you can't really go "off trail" in the woods.

 

You could always just notch the frame where the tires rub.