Rock Krawler 3.5 X-Factor

[Moto_21]

It is what it is. **results may vary**. Just know that MC and RK are pretty much neck and neck in the game, and obviously with MC's 3.5 of actual useable height after addons, it puts them at a better price point, especially given their kit comes with shocks.

Yeah I hear ya. I ordered my springs seperately because I noticed that the part numbers didnt match up on northridge, so I paid the $209 or whatever for each set and they gave me the $179 springs. I kind of feel cheated. Anyways Ill see what they tell me tomorrow.

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[Fizzlepop]

Between the 3.5 height before a body is added, the shock hitting the frame at flex, and the rear trackbar danger close to exhaust, I'll be recommending MC from here on out, for sure.

 

[Fizzlepop]

8 3/4 rear, 8 1/2 front are my measurements from center of tire to center of fender well. Less if I go from center of tire to fender lip. That means I gained 3/4 an inch in the front, and 1/4 an inch in the rear. That's with no weight addons.

 

[Moto_21]

8 3/4 rear, 8 1/2 front are my measurements from center of tire to center of fender well. Less if I go from center of tire to fender lip. That means I gained 3/4 an inch in the front, and 1/4 an inch in the rear. That's with no weight addons.

Damn barely anything over the spacers.

 

[Martindfletcher]

Here is what my RK 2.5 xfactor looks like with 37’s

I would prefer stiffer or taller rear springs,

 

[Jason]

When you say Jay, I am guessing Stomper? Anyway, I have the mopar, I think I am just under 3”, I have 37s, they only catch the fender in the rear, and its not bad. I have been debating switching to either RK or MC, sounds like MC may be my best bet.

 

[Rock Krawler Suspension]

We understand your concerns and will do our best to address them one at a time.

The coil spring seats. These are far from spacers. The first thing our engineers noticed on the JL was the coil spring bow was very noticeable. Coil spring bow may be intended by some, but we feel it is extremely unwanted and here is why. If a coil spring is bowing, it looses spring rate as it compresses and will fatigue faster over time. You will experience performance loss on and off road. Not to mention having your coil springs hitting the bump stops over every bump. The rear spring seats compensate for pinion rotation again minimizing spring bow and fuel loads.

The coil spring rates, travel, transitions and performance are exactly what we want you to have for your JL. The part number is just that, a part number. That number could be anything as long as it is right for the application. We offer lift heights in every inch from 2.5-4.5 for the JL Applications. We already have the 4.5 in stock but have not released the kits yet. Our lift heights are much closer to nominal on the JL and only over by 3/8 of an inch up front typically. We posted our spring rates as compared to stock, Mopar and others in another thread so if you want to look it up you can.

Our coil springs must be paired with our spring seats to not only provide proper lift height but proper performance. This is the first thread we have ever seen questioning them. All other threads praised the details and the corrections we have put into the JL. We know over time it will be very well proven. Look at the people who posted having Brand X Suspension and installed our spring seats to correct their spring bow and what the results have been.

If you are having issues with fitment or anything at all please reach out to our tech department. That is what we are here for. We assure you, we have installed and distributing a crazy number of JL kits already. We also know FCA is making some updates and changes as well so we are constantly running them through our building.

For shock applications possibly contacting the frame be advised that a crazy offset bottom mount will not work as well on the JL as it did the JK. The top loop mount for a heavily offset bottom mount should be a spherical bearing unless you are offsetting the top as well or you will experience rapid shock bushing wear. Our RRD Spec Twin Tubes will have slightly offset tops to improve frame clearances and not promote accelerated bushing wear. Our soon to be released RRD 2.25 will have offset tops and bottoms to improve frame clearances. You cannot just pair any old shock with any lift and think it is going to work right or optimize the ride and performance. It does not work that way.

There are a lot of similarities between the JK and the JL in many ways but a lot of the details are different. The JL when built properly is far superior but you must nail the details. Our tech support line is 518-270-9822 and we are always there to help. Even if you are not an RK customer.

Please note we are getting a major server overhaul tommorrow and over the weekend so our phone lines will be down. But hopefully everything goes smooth and comes back up first thing Monday AM as normal.

 

[Rock Krawler Suspension]

I'd like to start off by apologizing for my first thread being this type. I read the forums all the time and usually dont need to post as theres mounds of information. With that being said, I've not seen this posted yet.

Warning: slight rant ahead.

Brought my jl over for an alignment after installing my 3.5 X-Factor. There happened to be another JL that they installed a MC Game Changer on. 37s aside, I noticed that the MC jeep had more clearance between his fenders and tires than I did. I mentioned something about it, and Jay took measurements. Game Changer sat an inch and a quarter higher. Now, obviously regret started to settle in, but it was whatever.

I then remember the boxes being labeled as "2.5 inch JK front coil", so I called up RK and asked them what kit the part number for my coil goes to. She told me the JK 2.5 and JL 3.5. Then I'm told that it's because the JL is 300lbs lighter, so the spring sits higher.

On top of this, the RK lift came with new spring seats. These spring seats are more or less spacers, as they raise the spring off the axle higher than the stock ones. So, I have 2.5 inch springs, and a .5 spacer on a JL because it equals 3.5 on a bare bones stock rubicon. Not even a steel bumpers one.

So, some rough math puts undercarriage armor at 100 lbs. A steel bumper at 50, and a winch with line at 50. Tire carrier adds more, weight of a larger tire, etc. When it's all said and done, a reasonable trail rig will be sitting at about 2.5-2.75 inches on RKs lift. Mopar, MC, hell even skyjacker compensated by going longer to balance out.

To top it off, the passenger shock hits frame on flex(MC includes outboard shock brackets for this), and the rear sway bar bolts make contact with the frame on flex, and the track bar is within millimeters of hitting the exhaust. At this price point, and being top of their line, I cant even begin to Express the amount of disappointment in this lift. There is no reason a JL rubicon should look perfect with high fenders, a 3.5 inch lift, and 35s. It honestly looks like I'd rip the fenders off if I tried to flex with 37s. I've included a picture of my jeep post lift.

.

Are you planning on installing larger tires? 3.5 on Rubi’s are targeting at 37 to 40 depending on what you are doing with your fenders. Once you install the intended tire size on the rear it will sit much more to your liking. The rear spring rate on JL is 175-180 so it is soft. As far as the shock contacting the frame : have you validated the axle is centered side to side and what shock is it? We posted above regarding JL shocks with some fitment information. We hope that helps. If you want give our tech support a call at 518-270-9822

 

[Rock Krawler Suspension]

Here is what my RK 2.5 xfactor looks like with 37’s

I would prefer stiffer or taller rear springs,

Stiffer would of course ride firmer. Taller we have. We try to maintain a good quality ride while adding major performance improvements both on road and off road.

 

[Martindfletcher]

Stiffer would of course ride firmer. Taller we have. We try to maintain a good quality ride while adding major performance improvements both on road and off road.

I will confirm ride quality is awesome. Even the normal JL springs you put weight in the back and it gets a lot of drop. My comment was a preference one, related to the amount of gear I am usually hauling, also daughter and giant bull dog in the back..

I will probably upgrade to the 3.5 next year.

Oh and yes there is NO bow.

 

[Moto_21]

We understand your concerns and will do our best to address them one at a time.

The coil spring seats. These are far from spacers. The first thing our engineers noticed on the JL was the coil spring bow was very noticeable. Coil spring bow may be intended by some, but we feel it is extremely unwanted and here is why. If a coil spring is bowing, it looses spring rate as it compresses and will fatigue faster over time. You will experience performance loss on and off road. Not to mention having your coil springs hitting the bump stops over every bump. The rear spring seats compensate for pinion rotation again minimizing spring bow and fuel loads.

The coil spring rates, travel, transitions and performance are exactly what we want you to have for your JL. The part number is just that, a part number. That number could be anything as long as it is right for the application. We offer lift heights in every inch from 2.5-4.5 for the JL Applications. We already have the 4.5 in stock but have not released the kits yet. Our lift heights are much closer to nominal on the JL and only over by 3/8 of an inch up front typically. We posted our spring rates as compared to stock, Mopar and others in another thread so if you want to look it up you can.

Our coil springs must be paired with our spring seats to not only provide proper lift height but proper performance. This is the first thread we have ever seen questioning them. All other threads praised the details and the corrections we have put into the JL. We know over time it will be very well proven. Look at the people who posted having Brand X Suspension and installed our spring seats to correct their spring bow and what the results have been.

If you are having issues with fitment or anything at all please reach out to our tech department. That is what we are here for. We assure you, we have installed and distributing a crazy number of JL kits already. We also know FCA is making some updates and changes as well so we are constantly running them through our building.

For shock applications possibly contacting the frame be advised that a crazy offset bottom mount will not work as well on the JL as it did the JK. The top loop mount for a heavily offset bottom mount should be a spherical bearing unless you are offsetting the top as well or you will experience rapid shock bushing wear. Our RRD Spec Twin Tubes will have slightly offset tops to improve frame clearances and not promote accelerated bushing wear. Our soon to be released RRD 2.25 will have offset tops and bottoms to improve frame clearances. You cannot just pair any old shock with any lift and think it is going to work right or optimize the ride and performance. It does not work that way.

There are a lot of similarities between the JK and the JL in many ways but a lot of the details are different. The JL when built properly is far superior but you must nail the details. Our tech support line is 518-270-9822 and we are always there to help. Even if you are not an RK customer.

Please note we are getting a major server overhaul tommorrow and over the weekend so our phone lines will be down. But hopefully everything goes smooth and comes back up first thing Monday AM as normal.

Thanks for the info and clarifications

 

[River City Offroad]

I typed this up earlier before I spoke with JP about this thread and figure some of the elaboration might be helpful for you guys. I am not an employee of RK, but I am good friends with the guys up there and have supported their product line for many years in the JK world. I just want to be clear that I'm just here to help and try to do what I can for tech support since I'm on the forums a lot.

Regarding the shock hitting the frame on one side... Is your front axle centered properly under the Jeep? All lift manufacturer's measurements are a starting point for the most part and the alignment shop will generally have to square things up a bit. It is possible that the axle is kicked over a bit causing contact on one side but not the other. What shocks are you running with your lift?

Can you post or send me some pictures of the sway bar bolts hitting the frame and the clearance on the rear track bar along with a good picture of the Jeep from the side on level ground? I will PM you my cell # so you can text me if you want or you can post them here so we can discuss whats going on and hopefully answer everyone's questions.

I can tell you that the JLUR that RK used for R&D was a fully loaded model with steel bumpers. The coil "spacers" as you're referring to them are the correction wedges that replace the factory spring seats. These are necessary to keep the longer lift coils sitting straight in the vehicle. Mopar has adapted the same technology in their lifts and I have sold a lot of the RK spring seats/spacers whatever you want to call them to folks that are correcting other manufacturer's bowing coils with them. Rock Krawler designed them and Daystar is mass producing them and selling them as a Daystar product as well.

Here are the BOM for the 2.5 X-Factor and 3.5 X-Factor. These are their most complete kits, so if you have one of the lower level kits just omit the arms and such. The box

3.5" X-Factor for JLU:

RK03100 1 Triple Rate Coil Springs ( 3.5 JLU)
RK06693 1 Triple Rate Coil Springs ( 3.5 JLU)
RK06187 1 Front Adjustable Track Bar
RK06184 1 Front Lower Control Arms (Adjustable)
RK02028B 1 Rear Upper Control Arms (Adjustable)
RK06697 1 Front Upper Control Arms (Adjustable)
RK06190 1 Rear Lower Control Arms (Adjustable)
RK06692 1 Rear Adjustable Track Bar
RK06776 1 Box, Kit X Series

2.5 X-Factor for JLU:

RK04186 1 Triple Rate Coil Springs ( 2.5 JLU)
RK00215 1 Triple Rate Coil Springs (2.5 JLU)
RK06187 1 Front Adjustable Track Bar
RK06184 1 Front Lower Control Arms (Adjustable)
RK02028B 1 Rear Upper Control Arms (Adjustable)
RK06697 1 Front Upper Control Arms (Adjustable)
RK06190 1 Rear Lower Control Arms (Adjustable)
RK06776 1 Box, Kit X Series

Now, the coil springs are used across a couple of models in the RK lineup. I am repeating what I was told early on here when I questioned it, but the coil rates matched up almost identically to a factory JL and provided the nominal lift heights that they were shooting for on the JLU, so they made a couple of small changes to the end codes (windings) on the coils and kept the spring rates the same.

Here is the post from Rock Krawler where they shared factory JL spring rates along with the spring rates on the coils that RK chose to utilize in this platform:

“JLU Sport - 114/121 Front 171/174 Rear

JLU Rubicon - 123/128 Front 172/176 Rear

Mopar 2" Coils Lift - 131/133 Front 180/182 Rear

Our 2.5" Coil Spring Rates are as follows in the ride zone

137.5 Front at Ride Height

175 Rear at Ride Height

3.5" Coils are already coming in so we will give you those too

140 Front at Ride Height

185 Rear at Ride Height

The stock coils were dyno'd in house as well as at our spring supplier for confirmation of accuracy of rates."

Hopefully this helps and if anyone needs help feel free to reach out to me or tag me in your posts.

Marcus

 

[Rock Krawler Suspension]

I will confirm ride quality is awesome. Even the normal JL springs you put weight in the back and it gets a lot of drop. My comment was a preference one, related to the amount of gear I am usually hauling, also daughter and giant bull dog in the back..

I will probably upgrade to the 3.5 next year.

Oh and yes there is NO bow.

Just trying to help out my friend.

 

[Martindfletcher]

Just trying to help out my friend.

My comment was in parallel with yours I wasn’t complaining.

 

[Jergs]

Here is what my RK 2.5 xfactor looks like with 37’s

I would prefer stiffer or taller rear springs,

Looking good, Im glad my 2-door will net a little more height. Are you running wheel spacers on those stock wheels? If so, which ones?

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