3.5 "frankenstein" lift Questions/Ideas
 

Okay folks. As I become more educated to lifted vehicle dynamics, I start to realize that its basically impossible to find complete lift kits or kits with proper geometry correction, etc.

I have a 2012 JKU Sport. I will be running 37x12.5 Trail Grapplers, already have em. My axle and gears should be irrelevant here, but the front axle will be a built D30 most likely, possibly a D44. I will be eventually piecing together/purchasing a 3.5 lift and want to know the best way to go about it and what parts may achieve this for me. I am OCD and want my stuff to bring me peace of mind and be "proper."

I have had the Jeep for a year and haven't yet bought any real lift components because I want to be 100% educated and spend my money the right way on the right parts/brands the first time.

I am pretty set on using RK 3.5 springs. I know people complain about their trackbars, but having installed my buddy's, they are stout as hell and seem like as good a choice as any.

I have been wondering why RK's kits come with rear trackbar relocation brackets, and not front. Then I figured out. basically to raise the front roll center in order to correct the axle's side to side position, you need to also flip the drag link and have it even with the trackbar. Or else have crappy handling. I assume they have made their kits how they have because they wanted to keep price down, and it also lets them have another item to sell, the drag link flip kit. Business, right?

After looking into Synergy's kits, they offer the drag link flip and the raised trackbar brackets for a much higher comprehensive cost.

Synergys brackets raise the roll centers 3 and 4 inches from what I can gather. That brings me to my question.

Do the roll centers "need" to be equally raised front and rear? Does Synergy have different height brackets front and rear to accommodate for the factory rake they retain in their kits?

I guess I mainly have come here to ask the advice of the suspension nerds in here that know way more than I do, and more than I can figure out easily by searching various sites and kits and builds and parts.



Say I use the RK 3.5 springs and level out any rake that may be present. Or imagine that the RK evens the Jeep's height front and rear.

What would be the best way/best parts to correct the trackbar issues?

Am I correct in assuming that the roll centers need to be raised the same amount as the lift change? I do not want to weld on new brackets closer to the center of the axle unless someone here has very precise, definitive measurements of how to go about that.

What are the cheapest ways? I want to stay as cheap as possible, although have a high quality, "to the t" build.

What parts do you reccomend?

Should I piece together an RK "stock mod" but with 3.5 springs and trackbars and then add brackets to raise the mounting locations? Or buy some semi complete kit and go from there?

What is the best drag link flip kit for 3.5 inches on a JKU?

What control arms are truly the "best" taking into account money spent and overall durability through time? I will add control arms after the initial lift is done, I am 24yo and not loaded with excess spending money like lots of you middle aged fat cats on here lol. So I'm doing it in stages, unless I come into a large chunk of change for some reason. I see that Synergy has fixed length lowers. Does anyone sell a full kit of fixed length for all 8? The adjustability aspect complicates things and makes for a tedious install, which I will be doing myself. Does adjustability come with higher chance of wearing out the ends over time? This is my daily driver. Running 37s, I would like to eventually stretch the rear axle back 1in or so, to level the gap in front and rear of the tire in the fender well, we all know how it hits the pinch seam area, and the look of the tire being farther forward just bothers me.

If any of you suspension gurus who really know your sh*t, any manufacturers, weekend warriors, etc could maybe answer my possibly redundant, long list of questions, I would greatly appreciate it.

Even more helpful would be a list of parts/brands to use. I kind of have bias for RK and Synergy, but I usually forget about Currie and Clayton, which I know are also quality.

I really am tempted to just get the RK 2.5 Stock Mod sometimes to make it easy, but I know I will want 3.5in of lift in the end, and I want to properly setup the trackbars/roll centers the in the first stage. I do not wish to lift any higher than that. I was into LCG builds for a while and I want to maintain on road handling/enhance it as much as possible. Anything over 3.5 gets crazy expensive to do correctly and completely and on-road suffers also.

I apologize for the super long thread, but THANK YOU in advance if you can get through it all and help me become more educated and choose parts/brands. Like anyone does for their baby, (human or not :wink:) I want what's best for mine.

I ran the RK 3.5 mid arm lift with the RK front adjustable track bar and no drag flip and 37s without a single issue for years.

I would just get the adj track bar and if you run into steering issues, "which I doubt you will". Then get the drag flip.

Make sure you at least get the lower adj control arms.

I ran 3.5 RK w/synergy drag link flip & tie rod. Sold the RK track bar and put the stock back on when I flipped the drag link. Centered the axle and kept the two more parallel. Best option IMO.
if I was you I would be worried about 37s on a D30. Plus the other things like hydro-assist etc.

I'm riding my D30 until I break it. I figure no one is going to want to buy a D30 anyways and gives me justification to buy a new (44 or 60) axle.

best way to do it, when it breaks upgrade it, just make sure you are planning on the break and ready with the funds so you aren't down to long.
What gears do you have Bruce?

I'm running 4.88's now.

If I'm going to do the D60 I might want to go 5.38's because I want to run 40's. :yup:
That's a pipe dream right now but when it breaks I'm going to find a way to replace the axle--- trust me.

You do not have to have the front and rear roll centers the same. In theory you should run them as high as you can for stability. This is just one thing in the overall set up that will help with on road cornering and off road off camber situations. Coils, shocks, wheel base, track all contribute to stability on the jeep. A drag link flip will raise the front roll center, improve steering feel, reduce bump steer, and reduce axle shift. It will also cost you around 3.5" of up travel in the suspension unless you are going to notch the frame for clearance.

The rest of your questions are worthless as there is no best coil or control arm. What you need to look at is the clearance in the bends that you might need depending on your tire size and the joints they use. Don't get caught up in the hype about who has the most misalignment in their joints as you will never need any more then a standard Johnny Joint offers. Rake is there for a reason and not sure why so many try to level their jeeps, but to each his own.

Joints come down to 3 basic styles.
1. Clevite factory OEM Style which offer good ride and vibration elimination but lack the misalignment needed for shocks over 12" in travel. Cheap durable and rebuildable.
2. Ball and socket these range from Heim joints to Johnny joints and several others that are offered by several manufacturers. Typically they have a metal ball with a metal housing and run on some kind of bearing race that wears as time goes on. Most will have a grease zert and should be lubed after wheeling or at oil changes. They offer more misalignment over the clevite joint and you should never see any bind in them unless you have extreme travel in your set up. They tend to ride a bit rougher then clevite joints and Heim joint can be noisy over time. The joints are more expensive then OEM style but most offer rebuild kits. Heim joints are throw aways and you should also run safety washers with the heim joints.
3. The latest trend in joints is a modified OEM type joint that uses a softer rubber type compound with a steel tube molded in the center. The joints are not as wide as the OEM which gives them more misalignment while offering better vibration dampening then the ball and socket or OEM. The joints are rebuildable and the Metal Cloak uses a special grease when rebuilding. These type of joint are always in bind when flexing but there softer rubber type compound compresses easy to allow for misalignment. I find the MC joints to feel a bit squishy on my set up.


Good luck.

Amen!!

I know a lady that's run 40s on d30 with 4.10s for 4 years. Stupid, yes. She actually has 46s on it now, and yes she wheels it. No she isn't reckless with it. She just took it through some crazy mud adventures last weekend and the only problem she had was cutting trees to make it through the trails due to overall height.

I will be building the d30. You must not be familiar with Rebel Offroad. They've had plenty guys run and lock 37s on built d30s with absolutely no issues. I won't be going past 4.88 because of the smaller diff and everything that comes with that. I am not going to buy a new axle until I break. I have been in an accident recently where I bent the d30 and it barely bent from hitting a curb at 40mph to avoid a collision. I am more than confident that I will be okay with a gusseted and sleeved d30 with new shafts maybe also with my driving style offroad. This thread wasn't intended to be about axles and people trying to scare me into going expensive and bigger. There is no need. I am not taking jumps and it's my DD primarily. And based upon what I've seen others do and shops do, it is entirely possible to run a d30 on 37s if it's built and not be worried at all. Thanks

And that lady's axle is not warped or anything either. Her husband owns a shop and measures it often. They have 1tons for if and when she breaks or warps her d30. Has yet to happen.