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  1. #1
    Freaking JK Guru TheDirtman's Avatar
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    Southwest Reno, NV

    Rock Krawler 5.5" Trail Gunner Review

    Last week the shop I help out at from time to time installed the Rock Krawler 5.5” Trail Gunner kit on a 2016 JKUR and I took the opportunity to assist in the install and set up. The jeep already had a EVO 3” Enforcer stage 2 kit with Adams front driveshaft, pro rock 44 and king shocks with front king air bumps. I scratched my head a bit going from this to the RK kit but the customer gets what the customer wants. Here are some of my impressions of the kit.

    While the shop was researching and quoting the new kit the owner of the shop called RK for some approximate install times for the kit and was told it would take around 20 hours for the install. After buying the kit and going thru the instructions and set up there was no way it could be done in the 20 hours we were told. The shop owner called RK again and the person on the other side of the phone laughed when he stated he was told 20 hours and said it will take all week to do the install. In reality this kit took around 60 total man hours. I know I had 30 hours in it and there was someone there with me most of the time and there were people working on it when I was not there. I have do not have the total time from the owner yet. We blasted thru this build and didn’t mess around trying to maximize the travel out of every link or standing there studying the set up. We just installed it per the instructions (which were full of errors).

    The kit comes in a lot of boxes, just think of a standard pallet stacked two feet high. Each arm came wrapped in a plastic bag and then stuffed into a box with lots of paper for cushion. Most of the boxes were beat up and just looked shabby. Most people may not care about packaging but it is something I pay attention to and it typically reflects the care and quality that is in the box. Any that has bought an Apple or Bose product should have noticed the effort that goes into protecting a quality product in an environmentally friendly package. I just feel that seeing a product for the first time in a box that is beat up is a downer. Even the shocks were simply wrapped in a bag and paper cushioned. A company like King uses a foam surround that protects the shocks. Two of the shocks were also covered in oil and the shock bodies had several nicks and scrapes in them. The machining on the shocks had visible bad spots and the cheap stickers for the the compression and rebound make it look like the shocks were bought at Harbor Freight (a cheap discount tool store that almost everything is made in China). The shocks also do not come tuned at all and per the sticker on the shock “do not exceed 150 psi”. Most other quality shocks I have used start at 150 psi and go from there for tuning. The shafts are also not chromed and look to be honed and hardened. A few of the shafts had rough spots and nicks in the shafts. They are very light though I will give RK some love for being concerned about weight at least on their shocks. The rest of the kit not so much.

    After unpacking the rest of the kit some of the brackets come powder coated and some are raw steel. As most of the brackets are welded on since this is a long arm kit I would want them all bare metal as it just takes more time and money to remove the coating.The fit of some of the brackets was bad, I would say we spent 3+ hours just grinding brackets to fit for good welding. If we had not there were up to 1/2” gaps that would have been filled. The welding from the factory on the shock towers was pretty but you could tell the welds had poor penetration. A couple welds on the tower were around 1/2” gap fillers that looked terrible and the bracket was full of sharp edges. I would also note the towers are overly big requiring a lot of removal of plastic from the trays in the engine bay that hold things like the master cylinder and the TMPS. The towers are bulky and heavy and could be redesigned (improved) for better fit at a lighter weight.

    The rear upper shock mounts are just way too big for what you are doing and the fit again was poor. They use two legs that line up with the frame to locate. A couple of tips that could be included in the instructions is to cut off the legs when done and to place a removable shim above the bracket to space it away from the body or you will have rubbing on the body. This is a lot of work and time to gain very little in terms of travel as well as the expense of the bracket. The EVO upper shock bracket we removed would have been a better route to go with a shock that has a welded lower eye mount. Both of these things would decrease the cost of the kit and about 2 hours of install time.

    The rear lower shock brackets fit like crap. They are made to be bolted to the existing control arm/shock mount. The top radius is not cut out enough to clear the factory welds and the shock brackets are not Clarence to fit RK’s own shocks. The look of this bracket bolted to the rear axle just looks bad. It would be better to just remove the factory mount and use a good heavy duty replacement that would look better.This bracket came powered coated or painted. I would also note that the lower rear shock mount hangs down about 1” lower then the EVO rock stars for anyone concerned with clearance.

    The rear bridge went on pretty good. It was powder coated and we had to cut a couple notches in it to fit the axle vent and the ARB fitting that was installed in the axle. Not an issue for RK on the ARB line but I feel a well designed kit should not have to be modified for the factory vent line. Just more time and money on the install end.

    The rear axle side track bar mount is a weld on and RK has a rear track bar that has a couple of bends and a threaded joint on each end. This just looked like a dumb design and it is. They do this because of clearance issues mainly do to the poor design of their bridge and track bar bracket. The track bar mount is low and should be raised at least 1” and I would do 2” on the 5.5” kit. The bridge for some reason is pushed to the back of the axle and becomes a clearance problem if the crazy bent RK track bar is not used. The problem with their two screw in ends is that it makes it vey hard to keep the rod from rotating over time and takes a lot of torque on the jam nuts to prevent this. A set up with the bridge forward about 1/2” an inch along with a taller track bar bracket and a frame track bar that is moved back about 1.5” would allow for a straighter track bar that could use a fixed end on the frame side. This reminds me of their “anti-wobble joint”, they take their joint and put an o-ring on both sides to prevent it from rotating. This is laughable and just runs up the cost vs using a simple factory style clevite joint at the frame end.

    Note that the coils contact the bridge at ride height. We cut the factory perches off the axle and moved them out 1/2” as well as rotating them to the top of the axle so we could eliminate the dumb coil wedges.

    Up front the big heavy drag link looks massive until you look at the steering box end where it re-uses the factory link end. Another component that just runs up cost and weight.

    The arms are heavy and the powder coating was so so with lots of dust flecks and some rough spots from the shipping. The ends on the arms are not fully welded and look incomplete. I would not think they will break off but it just shows the lack of attention to detail. The front frame mounts were too tight for the joints and had to be adjusted with a grinder so the joints would fit. This bracket was also powder coated.

    The lower front shock bracket mounts to the bottom of the axle unlike the EVO double throw down (we installed this kit on a JKUR last month) which cost you some clearance under the axle. It is narrower then the EVO bracket so the shocks sit more parallel but we had to cut off the bolts because they are too long and hit the axle tube. we also had to use steel lock washer vs the nyloc supplied with the kit because they would not fit.
    We set the brackets so both shocks were fully extended at the same time. This allowed the bypass to go to full bump while the coil over had just over 1” of shaft showing.

    The reservoir mounts to the side of the tower and could be better. On the passenger side you have very little clearance to the exhaust sensor. The bypass bracket works (we were missing one so had to zip tie it in there while we waited 9 days for the replacement to get here) I think RK should spend some more time fitting these into the fender wells. Something better then cheap hose clamps should be used on a $15,000 lift. Not sure why they don't mount the reservoir to the body like others do but the fittings and hoses look just thrown together. On the rear we built mounts to the body cross support instead of drilling thru the body.

    When finished with adding about 2” of preload on the coil overs we ended up with about 4.25” of shaft showing on the shocks and a relatively level ride. Ride height was good and low and top of windshield around 77”-78” with the hard top on at the top of the windshield. All the shock shafts show visible oil residue. Not sure if RK uses race seals made for hot running as this is typical of those type of seals.

    When it came to “tuning” the shocks we followed the instructions and made all the adjustments then found out the directions were wrong after calling and talking to RK. Another hour wasted. We took it for a ride and it felt stiff and very rough at low speed over bumps which is what you typically expect from this type of suspension. The ride performed better at speed, going over a set of tracks at 60 mph was decent. There is quite a bit of rear squat under acceleration and same with the brake dive. The rear end seemed loose on the pavement. We did a short amount of off road and it was jarring with lots of side to side movement. It would really not be comfortable on a long trip. The adjustment valves are inconsistent with every valve having a different measurement at the bottomed out mark. Disregard the instructions and the .136 measurement in the photos because non of the bottoms was close to this measurement.

    We parked it that night and the next morning we had oil leaking out of two shocks and the owner showed up to take it for a ride. After about 15 min he cam back and looked somewhat disappointed and stated the ride was too stiff so it is scheduled for some more tuning. Hopefully we can soften up the ride a bit with the shocks. The owner also has 37’s on 20 with an E rated tire and is aware of what this does to the ride quality.

    In summary this kit is so so with a lot of room for improvement and cost reduction. Anyone that has read my post in the pas knows I am no fan of Rock Krawler or Off Road Evolution but after installing this kit my impressions of RK dropped from middle of the road to bottom of the barrel. I would recommend Rough County over Rock Krawler today. If using this kit I would go with Fox or King shocks with welded lower mounts for more useful travel. As far as fit and finish this is the worst kit I have ever installed and attention to detail is an afterthought. The kit is heavy, very heavy when compared to other kits out there. This kit is comparable in components to the EVO Double Throw Down and while there are several things about that kit that could be improved it is a much better kit then this mainly due to the shocks, weight, and fit and finish. I truly feel that both of the kits use too long a travel of shock and lack up travel for the level of performance you should get from a coil over bypass set up.

  2. #2
    MallCrawler icrashbikes's Avatar
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    This is a good review. It's unfortunate that the quality from RK is so poor, I'd have hoped for better from a reputable brand. I know you tend to be anti-kit in general and your insights have helped me more than once to break out of that kit-focused mentality. Thanks for an interesting read

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