Still Weighing Lift Options for 2008 JK 2-Door Rubicon

Hi,

Making the decision to buy the new Rubicon was sure a lot easier than deciding on which lift kit (and height to install). There's a lot of great advice on this forum, so I thought I'd ask for some more advice. (I posted in December and received a lot of feedback; but, I still don't feel I have enough information to make a good decision. It would sure be great if someone would put together a detailed spreadsheet showing the good and bad associated with each system. Is that something that would be of interest here if I took the time to do that?)

I'll apologize in advance for the length of this post. I just want to include as much information as possible, and ask all the questions I can think of before submitting this post. I hope it's not overkill. I know there is a lot of experience on this board, so I'm hoping that there are opinions on a lot of the questions.

The following are the specifics that will go into the selection of a lift kit (and other required parts):

1. Tire Size: Initially stock 32s - upgrading to 35s within a short time (or possibly upgrading to 33s depending on answers to some of my other questions).

2. Lift Height: 3" to 4"

3. Installation: DIY (Prefer No Welded Components)

4. Drive Conditions: Trails, Rocks/Slickrock (Moab), Highway, and City (It's tough to say what the mix of conditions will actually be long term.)

5. Additional Add-Ons to Consider (i.e. Weight): Winch and Heavier Front and Rear Bumpers (In other words, I want to make sure the springs are capable of the added weight.)

6. Other: 1.) Stable / Safe Road (Highway/City) Driving. 2.) Reliable Components (Long Life). 3.) Great Engineering (Complete Package for Installation). 4.) No Interference with ESP or Other Jeep Systems.

Questions:

1. Drive Shaft Replacement: Once a decision is made to replace the driveshafts, should both the front and the rear be replaced at the same time, or is one more critical than the other? (Who are the respected manufacturers?) (This is a topic that gets ignored by a lot of reviewers and manufacturers, yet there are Jeep enthusiasts who have a very strong opinion that whenever the Jeep is lifted, the drive shafts should be replaced.)

2. Tire Size Considerations: I had decided to go with 35" BF Goodrich MT; but, from what I have read, it may be a good idea to be more conservative. Although I'll lose something in clearance, the reduced weight of the tires won't stress the driveline as much. Would I be making a mistake by going with 35 inch tires when I consider the life of the Jeep?

3. Adjustable Control Arms: Should adjustable control arms for the front and the rear be installed along with the lift kit for a 3"/4" lift? Or, is the front (or rear) more critical? If the lift kit doesn't include adjustable control arms should I not consider it?

4. Shock Absorber Type: Twin Tube? Monotube? (Are the higher pressures of the monotube shocks a problem?) Which type is better for crawling? Which is better for highway? Is there a preferred manufacturer? (I understand that lift kit manufacturers provide shocks (or options for them) with their systems, and that they should be matched to the springs for that system.)

5. Brake Line Extensions: For the kits that include relocation brackets only, will there be enough travel? Or, should brake lines be extended to be safe?

6. Body Lift: Should lifting the body be considered? Or, is it best to stay away from body lift for the JK?

7. Jeep Warranty: Is there any kind of unwritten rule about how much modification can be done to the suspension (i.e. lift) or driveline (i.e. driveshaft replacement) before the warranty is voided? Typically, will a modified suspension or driveline void the warranty on the engine / transmission / differential?

8. Manufacturers: 1.) Teraflex. 2.) Black Diamond (3"). 3.) Superlift (4"). 4. Rubicon Express. 5. ARB OME (Is there an OME JK kit?). 6. Nth Degree (Is there a 2-door kit?) 7. Fabtech  I have read a lot of good things about OME; but, I can't seem to find a JK kit (I did find a reference number, but, it doesn't get me anywhere). Is there any other manufacturer worth considering? (I know this may be a preference as much as a recommendation.)

If you've made it this far in this post... Thanks. Any information you can share will really be appreciated.

Thanks

Jeff  

howdy Jeff, sounds like you have already done your homework and got the right questions.I can not claim to be an expert as my 07 jk i still stock and will be for some time but i am asking all the same quesions.If you haven't already be sure to check out jp's project jk as they have already addressed most of these issues.Really the most important thing is tire size/type.All other mods depend on tire choice,go to big and you will need gear changes and or axle housing upgrades.35" tires seem to be the good middle of the road choice with 4.10 gears and stock components but you still may end up braking stuff.Plan on new driveshafts regardless as its good insurance.Mopar likes the Rubicon Express 3.5"and 4.5" long arm kit and so do I. While these opinions are borrowed from JP and others T can't speak for them,you will have to read up and chose for youself.Extended brake and esp/abs lines are critical as well as adj. control arms.The big choice is short or long arm,both have pros snd cons.Me personally I hope to get the R.E. long arm 3.5" kit for my 07 4dr as the long wheel base needs the height to get over stuff,it is more complicated to install and my warranty will be expired by the time i get it but if Jeep likes it so do I.Take your time and read alot before you purchase,this site has everthing you need to know but it takes time to find it,not to say the site isn't organized well there's just alot of forums to read through.Good luck and let us know what you choose and send pics.Andrew  

Springs and shocks. Make sure they are tuned to the vehicle and to each other. Longer is just the starting point. A lot goes into good spring and shock design. The "lift kit" guys just don't do it. Their only emphasis is on "lift" and price points, for the most part.

Don't get cought up in the JK long-arm crowd, especially for only 35" tires. The JK is not a TJ and the long-arm made sense for the TJ. The stock JK is already a long-arm compared to the TJ.

A 3" lift on the JK is very mild and can handle 35's with no problems. Don't lift it more than 3". It's not needed and the lower the better for all around great performance, on-road and off-road.

Don't confuse "Jeep" and the "dealers" that sell Jeep vehicles. Dealers put all kinds of junk on the vehicle that would make most of the Jeep engineers cringe. In fact, I'd almost go as far as "If the dealer did it", beware!

It is against federal law to just void a warranty because some after-market stuff was installed on a vehicle. It first has to be proven that the after-market part caused a particular problem. So, you are at some risk, but not holding the bag for everything that may be a legitimate warranty claim.

Premature driveline cv joint failure would be a case in point for a lifted JK. You need to budget for new driveshafts.

This is all covered under the "Magnuson-Moss Warranty Act" and complaints will be handled by the Federal Trade Commision. So, understand your rights if you're concerned about the warranty.

AEV, which sells Nth Degree suspension systems, is a special kind of company. They have several former Jeep engineers on staff. A lot of "lift kit" companys use canned engineering, meaning the proper testing of the end components has not been done. They are basically fab shops. When in question, "over-build it" is their motto. Sometimes other areas of the vehicle that are not changing need a little engineering to make sure undo forces are not going to be a problem.

This approach often leads to failures elsewhere on the vehicle. They build a big heavy-duty bracket that does not break. But it causes some "unexpected" forces to be placed elsewhere on stock unmodified areas of the vehicle, causing fatigue and breakage.

AEV builds great stuff. Not only for enthusiasts, but also for Chrysler. They have designed and built, and received design awards, for many Chrysler prototype projects.

AEV's kit isn't the cheapest, but you'll be getting top notch, well designed and tested products.  

Thanks for clearing that up for me you mentioned many details i haven't read before.I certainly don't want to mislead anyone with my lack of knowledge, I guess it proves the saying"You don't know what you don't know".So if the short arm kits are good for the jk what's the advantage of the radius long arm? I guess this type of stuff is why I'm going to wait to modify mine so I get it right the first time . I will also try to beter about jumping in on posts when my knowledge is lacking.  

nourlmt:
Thanks for clearing that up for me you mentioned many details i haven't read before.I certainly don't want to mislead anyone with my lack of knowledge, I guess it proves the saying"You don't know what you don't know".So if the short arm kits are good for the jk what's the advantage of the radius long arm? I guess this type of stuff is why I'm going to wait to modify mine so I get it right the first time . I will also try to beter about jumping in on posts when my knowledge is lacking.




I don't think you said anything wrong. I'm just putting my opinion, along with a little information, out there.

One thing that I did not mention was gearing. You'll want lower axle gearing than 4.10's for 35's.

Depending on the tranny, at least 4.56 for the 6spd and 4.88 for the 4spd auto.

You'll also want a correction box to generate the correct speed signal to compensate for the tire and gear change. The factory computer can only be changed up to 32" tires and 4.10 gears. AEV also has just come out with one. Pro Comp also has an Accu Speed box, but it cost a little more than the AEV box. I think Dakota Digital's box might also work for the JK and it's only $80. I know it works fine for the TJ Rubicon, but not sure about the JK.  

Hi Andrew,

Thanks for both of your posts. I thought both of them were great. It appears that a lot this topic has to do with personal preference. Except for some extreme issues, it's kind of hard to believe that it's either right or wrong. For that reason, we could probably both research this to death, and then we'd miss the fun of the modification, and of putting it to good use.

I also appreciate your comment about the JK-Forum. I had visited there before, but, I never really dug down to the details. There is a lot of great information there. This forum is great, too. Everyone that posts has a different perspective. That's what makes this so much fun.

Thanks again for posting. Please continue... we'll all learn.

Jeff  

Hi ftgiles,

Thanks for your post. It's great to hear from someone with so much experience. Every time I begin to think I understand what I'm reading, I read another point of view that makes me rethink everything.

The issues that are really sending me in circles are the lift height and the driveshafts. I have read a lot about the 2" ARB Old Man Emu setup, although it appears that there are quite a few options to be added to the quality shocks and springs they sell. At a 2" lift, are new driveshafts still critical in your opinion?

I agree with your suggestion of going no higher than 3"; but, I'm interested in knowing if you think that 4" (short arm) is acceptable?

Your warranty information is great. I know that when I bought the Jeep last fall, and mentioned lifting it, I got a speech from the salesman about voiding the entire warranty. After some deeper discussion I began to realize that it's a pretty subjective thing. I guess we'll just have to see how it works out.

Thanks again for your input. I'll look forward to more of your input in the future.

Thanks

Jeff  

ftgiles thanks for that last post i think i get a little post happy sometimes and don't always think through what i'm saying, it's easy to leave out all the realative thoughts in my head that make my comments make sense to me. i was drawn to this site because of the good information and i don't want to decrease that. your comments about aev made me realize how much more info there is out there. i've always liked aev's products but have not seen much advertising or articals/reviews for the jk stuff. my dealer tossed me the RE catalog when i was talking about mods and i see their ads all the time. and to be clear my dealer wasn't pushing re on me just showing me his options, actually he thinks i should keep it stock and wheel my 99 xj that's paid for,can't say i blame him that's probably a good idea but the roof doesn't come off easily. the subject of warranty never came up and think he would do anything he could to fix my jk under warranty, i got lucky my dealer is awesome,not only does he run the oldest car dealership in town but he is a great guy and only sells jeeps and wants me to get the most for my money. the reality is my jk has never been stuck,probably wont get stuck for along time so i really don't need to do a thing to it but drive it. lack of legal wheeling trails and money for repairs and a much more reasponsible attitude have put a crimp on my offroad time. so thanks again for your well written posts and great info i always look forward to what you have to say.