2017 Jeep JK | Synergy 8″ Stretch
One of the oldest debates in wheeling, and off road vehicle build theory, revolves around the ‘ideal wheelbase.’ No matter where you end up wheeling, certain obstacles might click with your wheelbase and make you look like an old pro; others might prove to be your nemesis and force you to pull the cheat cable no matter how many times you try it. When Jeep released the JK, not only did the 4 door variant feature a significantly longer 116” wheelbase than the outgoing TJ models 93.4”, even the 2 door JK had a slightly longer wheelbase at 95.4”.
In a nod to mass appeal, the 4 door JK’s ended up sitting relatively low, and need to be lifted 4+”on 37-40” tires to fully take advantage of the long wheelbase potential in true crawling conditions. In other words, unless you are ready to go to 1-tons and 40s, you’ll probably be dragging belly in a lot of places. An astute or Jeep-educated reader might also notice, this left a glaring gap in the lineup…right where the 103.4” wheelbase of the departed LJ sat. For many years, fab shops and home fabbers alike have all been stretching TJ’s, YJ’s and CJ’s alike to get into the goldilocks wheelbase zone: over 100” and under 110”.
Our friends over at Synergy, recognized this issue early on and came up with an interesting solution…their 2-Door JK long arm stretch kit. Building off of their already extremely proven and successful JK long arm conversion kit, Synergy engineered frame brackets that would allow the long arms to push the wheelbase back a whopping 8”. Doing the math we see that it puts a 2-dr JK right around the same wheelbase that an LJ had, but with the added bonus of being built on the more modern JK platform. This wheelbase strikes a perfect balance between the nimbleness and excellent breakover clearance of the stock 2-door, but with the added stability of a longer wheelbase for better performance on steep climbs, waterfalls and ledges. As a 2-door is a good bit lighter and with a shorter body than a 4-door, the departure angle improvement is tremendous, and you also get to reap the benefit of longer wheelbase without all the extra body weight of a 4-door.
At the core of this system, is Synergy MFG’s tried and true JK long arm kit. The rear stretch kit uses the same control arms as their standard long arm kit, but with unique bracketry designed to move everything further back down the frame rail. A new, weld on track bar mount is included for the frame side bracket, this is an ideal time to include an adjustable rear track bar in your build plans, as it is necessary to properly center the rear axle. As one might imagine, this system is certainly not for the timid…once you cut the factory brackets off you’ve passed the point of full commitment. Luckily, the control arm brackets still index off of factory holes, so ensuring everything ends up in the right place is easy. As everything moves along way from its original home, a great deal of time is necessary to cycle, trim, check and repeat to ensure nothing interferes as the suspenion moves through its range of travel.
When making the leap to a longer wheelbase 2-door JK, there are a couple ways to go about setting up the rear springs. The original version of this stretch kit, was coil over only, but Synergy has since released an additional version designed to reuse standard issue JK rear coil springs to help cut down on overall cost and simplify vehicle setup, as not everyone wants the added complexity and tuning complication of coil overs. In this case, our customer isn’t shy of adjustability and opted to go for one of our favorite coil overs: Fox Factory Series 2.0 with DSC. These coil overs are a great option, their 2.0 body size ensures easy packaging in the tight confines of a JK, and affordable springs with a plethora of spring rate and length options. They feature the signature DSC equipped reservoir used on the bigger 2.5” body coil overs, so you gain independently adjustable high and low speed compression valving, as well as more oil and nitrogen volume for stable performance under demanding usage. To keep overall build height low, 10” travel shocks were chosen as a great compromise between wheel travel, low COG stance, and no intrusion into the passenger compartment.
As this vehicle came to us with Currie Rock Jock Dana 60s front and rear, and the front long arm conversion already done, we were able to completely focus our efforts on building the rear suspension. To round out the package and balance the Jeep out with the front, we added a rear Anti-Rock sway bar from Currie to complement the front Anti-Rock, and our own ‘budget bump’ slug, which allows you to run a urethane bumpstop in a standard 2.0 air bump can; on this Jeep we used Synergy ‘single pinch’ cans, which are well suited to being frenched in the frame for maximum clearance. This sets you up nicely for Fox 2.0 air bumps for down the road, as you won’t have to re-do the work when time and budget allow. When tackling a swap as invasive as this, it’s important to take the time and cycle everything for proper clearance and fitment, contact us today if you’re ready to take the plunge!
