http://www.wranglerforum.com/f202/beginners-guide-to-lifting-your-jk-298665.html

I think you would have better luck posting this here

 

Pretty much the same modifications for either. Exhaust spacers for the front or a after market DS. In the rear you maybe able to run the stocker on a 4 door.

 

3.5". I went back and forth on 2.5 vs 3.5 and so glad I went 3.5. That inch has made a difference while wheeling.

 

Go with the 3.5'' you will be much happier with the height especially with a 4-door. Ken is right the rear ds will be fine but you may want to change that in the future also. The front you will need spacers or the DS if planning on any offroading.

depending on what else you have on the jeep the kit will level the vehicle. Mine has a slight rake but I have no weight in the rear.

lets do this
1. with the 3.5'' you will have better clearance which is needed with a 4-door if you have a 2-door 2.5'' will be enough

2. your just adding extra pieces that aren't necessary, 2.5'' with spacers is just a pieced together 3.5''. buy a complete system.

3.This will be a never ending debate but, whats needed...nothing, if you plan to offroad I would get the front DS or spacer and run it till something breaks. I have this kit with 4.88 gears and I haven't upgraded anything yet except exhaust spacer.

4. I can only speak for the 3.5'' and no mods are required except drilling a few holes for TB bracket and spring clips and sway bar.

5. It does not need a leveling kit but again that all depends on the weight you have.

6. That's mostly going to depend on shocks, extended lengths and compressed lengths.

 

The difference between the two kits comes down to a tradeoff between cost and overall reliability vs off road performance. There is no doubt the 3.5" provides more articulation and room for the tires to work but it comes at a cost. The 2.5" is designed to raise your Jeep to the threshold where other parts are required and to reduce the loads on joints and the driveline. If you trim your fenders or add a set of flat ones you can get about 85-90% of the performance of the 3.5" lift. If you add driving skill to that they become pretty close to equal except on the most demanding obstacles.

If you are not driving off road at least 20-25% of the time most owners are better served by the 2.5" class of lifts particularly if it is your DD.

 

Go with the 3.5. I DD mine and have put almost 20k miles on my RK X factor kit. I paired it with the rancho 9000s and duratracs. My wife drives it and she'll even tell you it's super smooth and responsive. Drives really well. You will regret the 2.5". I run an exhaust spacer and haven't had any troubles with my drive shaft....after multiple wheeling trips and the 20k miles.

 

My wife had a 2013 JKU with the most popular combo, (2.5, 33s, 9000s. it was her DD and she/we wheeled it relatively hard. It's mine now. She now has a JKUR with the RK 3.5 and 35's as her DD and she nor I will ever look back. I will be doing some major changes to the JKU after I get done spending a small fortune and weeks at a time under her Rubi. BUT that was us and what we determined we neede. We are seriously happy with the 3.5 RK X factor.

 

Are you planning on changing your TF 2.5 to the RK? I'm really curious to hear your input since you have first hand daily knowledge and experience with these two kits.

I have the TF 2.5, 35s, 9000s and I am thinking about just changing springs to RK 2.5 or making some major changes and going RK 3.5. How does the daily driving compare between the two?

 

My 2013 handles extremely well in corners and provides a bit smother ride. I have and still do wheel it fairly hard for all the more ground clearance it has. JKU on 2.5 lift and duratrac 33s. (not great ground clearance. But for off camber it is like a spider, all though a short legged one.

The RK 3.5 and 35s ride on highway quit nicely, cornering is not what I would call bad but would compare it more to a pick up truck. It corners plenty fine for us. Now this vehicle is a Rubicon and of course has lockers and more aggressive tread so it's not an apples to apples comparison. It handles really great off road, it has much more belly clearance than mine so if you like rocks as we do, that is importaint. The RK suspension is absolutely potent. You wont break it, you wont bend it. Many folks go to a Teraflex monster track bar because its easy to adjust. I stuck with the RK that came with it, simply because they are solid heavy bars that really only need to be adjusted one time, unless you plan further changes, but certainly not a daily task.

I'll tell you, what it boils down to is what are you going to do with your Jeep. Do not lift it any higher than you have to. I would not personally go higher than 3.5 with a JKU or 2.5 with a JK. I do however want taller tires which will require gearing and reinforcement.

If it were a dedicated OFF road only vehicle, this discussion would be entirely different story. But my wife and I drive these to work, I drive mine into chemical plants and take customers to lunch.

If I pick up a 2017 JKR, I will be making some major changes to our 2013. HD 44 up front RK 3.5 and 37s and 488-513 gears ARB lockers.

Neither of those companies will disappoint you just have to decide what you now need and try to anticipate what you will want in the future. I'm beginning to see that as part of the fun of it all. My wife is the same way and that makes it really great.

 

Thanks for the info. I'll be honest, I don't really offroad much. Just the beach and the ranch which has some decent mud puddles. I'm mainly in it for the looks, I know, I know. I feel like my TF 2.5 needs to be a little higher to have the proper proportionate look with the 35s.

I also feel like my TF 2.5 ride quality has gotten a little worse over the past year. It's fine when just cruising buy doesn't seem to handle smaller road imperfections very well. I was thinking maybe that was because of the linear spring rates and the added weights of bumpers, etc. So that's why I was kind of thinking about changing to either RK 2.5 springs or just jump on in to RK3.5.

 

Do you plan to Offroad your Jeep? If not or just mild fire roads type stuff, 2.5. If you plan to crawl rocks and obstacles, 3.5.

 

I have ran some 20-30 plus mile ranch roads into various wind farms for work and ranches we hunt on, (allot of miles). Those roads are tough on vehicles because you are rolling much faster than you would on trails. They beat on your ball joints, tie rods, and of course springs and shocks.

My choice would be the RK springs in 2.5 for your use. I have had incredible service from Rancho 9000 shocks in these environments, and you can dial them in to the level of stiffness you prefer. I've never had a fade issue with them under these conditions. You mentioned the look of your 35s on 2.5 lift, have you considered flat fenders or trimming your OEM fenders. That alone will make your 35s look very good proportionally speaking. If you go to 3.5 springs you will most likely have drive shaft and castor issues to deal with.

 

Yes I think fenders are in the near future. One thing at a time From what I hear and read, it seems like the RK 2.5 springs might net me about 1/2" higher than the TF springs. That coupled with the new fenders might be just enough to fit my eye right.

What do you keep your 9000s set at for street driving. I currently have mine at 2. Wonder if I went stiffer if it would feel better/tighter.

 

I have the RK 2.5" X-Factor with stock fenders and KM2 35s. It actually ends up at around 2.75" and I have heavy front and rear bumpers and a winch. Glad I went 2.5" and not 3.5" for 35s. I have no need or desire to go to 37s right now and IMO 35s would look a little odd on the RK 3.5". Local "experts" told me to keep the center of gravity as low as possible to get the job done. If the job isn't getting done it's an easy matter to go to 3.5". Changing to 3.5" later only requires a new set of springs for the X-Factor + all the other stuff people mentioned.

Going to 35s triggered another round of spending since I have a Dana 30 front. At the moment I am replacing the front with a Dynatrac PR44, re-gearing to 4.56 (I have a stick), chromoly rear axle shafts, front and rear drive shafts, and Eaton e-lockers front and rear. Doing all this work at once will save money as opposed to doing it piecemeal. - That's what I tell myself as justification.

 

Yes, that D30 will practically explode on 35's. :whistling:

That wasn't a serious remark, and the sarcasm isn't directed at you. Since you're not going higher in tire size, you'll be fine with just a little bit of money into that D30 on 35's. That is, of course, unless you WANT that PR44, which changes everything. So basically I'm saying this under the appearance that you may think you NEED to get rid of the D30. Please wear whichever one fits and disregard the other

 

Like others have mentioned, it really is up to how you use your Jeep. If you feel someday down the road you will want to run 37's or 38's with flat fenders, go to 3.5". Or in our opinion, 3.5" of lift with 35's and OEM fenders looks very nice as well. It has a nice lifted look to it...

RK