FOX Performance Series Shocks Jeep Wrangler JK Review

Jun. 24, 2013 By Jaime Hernandez

Sometimes Jeeps just need some love. We run them hard day in and day out, carving on the asphalt and making them live up to their “Trail Rated” emblem every chance we get. Our four-wheel drives give us the freedom to cut loose from paved roads, taking us to amazing places. That said, a little TLC for your Jeep can make this dirt slamming life much, much smoother. The best place to start is with your suspension.

Our friend Brian had lifted his Jeep Wrangler JK 2.5 inches using coil spacers and was still running the factory shocks. He knew that at some point they would be replaced with longer ones to take advantage of all the wheel travel available. After adding TeraFlex Quick Sway Bar Disconnects, the shortcomings of the factory shocks became even more evident. The front axle was moving around more, and at extreme articulation, the shocks were maxing out. 

We sought help from the ride gurus at FOX. We spoke with Brian Godfrey, Marketing Manager at FOX, about our short shock problem and how we really wanted a smoother ride that would seamlessly provide control both on and off-road. FOX had come highly recommended to us from Mopar, Off Road Warehouse (ORW) and TeraFlex. Godfrey suggested we try their new FOX Performance Series Shocks, which are designed and tuned specifically for our lifted Jeep Wrangler JK Unlimited. Fox Performance Series Shocks are also designed and built in the USA. 

We thought, “If they are anything like their racing shocks, we’re in good shape.” FOX has a deep heritage in off-road, stemming from the first motocross shocks built by Bob Fox in 1975. For over three decades, FOX has been an industry leader in the design and development of high-performance shock absorbers and racing suspension products for snowmobiles, mountain bikes, motorcycles, ATVs, UTVs, off-road cars, trucks, and SUVs.

Bob Fox, founder of FOX, testing dirt bike shocks in the ‘70s (Photo Compliments of FOX).

For years off-road enthusiasts have been modifying Fox Racing Shocks to work in their daily drivers. Many times they required custom fabrication, tuning and sometimes even running a shock too long or too short for the vehicle. FOX has finally come to the aid of the off-road enthusiast looking for a direct factory replacement for stock and lifted suspension. The FOX Performance Series Shock are made with the same quality for which their racing shocks are known. This all-new lineup delivers race-dominating performance in an affordable, hassle-free, bolt-on package for all popular trucks and SUVs.
The new FOX Performance Series Shocks are available in 2.0 Smooth Body, Reservoir and Coil-over IFP applications. The silver aluminum body is accented with black anodized 6061-T6 billet aluminum mounting hardware.

The FOX Performance Series Shock features a one-piece, metal-impacted aluminum body that dissipates heat three times faster than conventional steel. Inside, an Internal Floating Piston (IFP) separates high-pressure nitrogen from specially formulated oil, engineered to deliver ultimate performance at variable temperatures and speed.

FOX’s race-developed high-flow piston design is used in the Performance Series. The Internal Floating Piston (IFP) isolates the shock fluid from the high-pressure nitrogen charge, assuring maximum damping and sustained fade-free performance.

The FOX Performance Series is perfect for daily drivers that also like to get dirty. This new line of shocks provide an easy, bolt-on, application-specific performance package that will deliver a comfortable ride that is capable of handling the roughest roads.

Large 5/8-inch diameter shaft is chromed and induction-case hardened to more than 55 Rockwell to defy pitting and scratches that can damage shaft seals. The redundant sealing pack system includes a main seal, wiper seal, and scraper seal to assure the elements stay outside the shock body where they belong.

Adding FOX Performance Series Shock absorbers can be done in your driveway using a set of wrenches, some standard suspension tools and muscle. If you’ve actually been using your Jeep in the dirt, we applaud you. We also suggest you wash off your undercarriage before starting work. If the bolts fastening your shocks seem corroded, spray some WD-40 or Liquid Wrench to make it easier to loosen the bolts.

The following FOX Performance Series Shocks were used on our Jeep Wrangler JK Unlimited with 2.5-inch suspension lift:

FOX980-24-887 - Front
FOX980-24-888 - Rear

The nice thing about swapping out shocks on a Jeep, and most solid axle 4x4s for that matter, is that it can be done without jacking up or putting your rig on a lift.

The front of the Jeep JK suspension calls for a pin (top) and eye (bottom) shock mount.  The “pin” resembles a vertical bolt. It fastens to the frame and runs parallel to the suspension coil. The bottom ties in directly to the front axle housing bracket. The top of the shock needs to be secured before the bottom is fastened.

The OE Replacement Bilstein Shocks (top) runs the shaft on top and body on bottom. The new FOX Performance Series shock runs the body on top, shaft on bottom.

When bolting up the front shocks on the JK, we quickly learned that if the lower bolt head does not face the correct way (inward), it can potentially cause some clearance issues with the lower control arm.  Pay close attention when removing the old shocks as this will come in handy during re-assembly. TIP: Use technology and snap some photos using your smart phone for reference.

Since the FOX shocks are pressurized with nitrogen, getting the lower shock eye lined up with the bracket did take some muscle and a several tries. Having an alignment pry bar will come in handy during this step.

The front shock lower bolt needs to face inward, with the bolt head facing the lower control arm. This will assure there is no clearance issue. Getting it backwards may cause the bolt to rub on the lower control arm.

The rear shocks on the Jeep Wrangler JK are eye to eye, meaning both top and bottom ends use a horizontal bolt or stud to secure them to the frame and axle. The top of the shock comes with a T-bar already installed, which uses two bolts to fasten on the frame.  The bottom uses the factory bolt, which installs into the shock bracket on the rear axle housing. Having a pneumatic impact gun will help remove the top bolts much faster.

Once the shocks are installed, it doesn’t hurt to torque them down to the recommended factory specs with a torque wrench.

Front Shocks
Upper Nut 20 lb•ft
Lower Bolt 56 lb•ft

Rear Shocks
Upper Bolt: 37 lb•ft
Lower Bolt: 56 lb•ft

The front shock top pin can be tricky to tighten, as they tend to turn the entire shock body when torquing down. Look for a machined Allen head on the top of the pin. Using an Allen key, the installer can keep the shock from turning. There are also some non-marring wrenches that can be used to secure the shock during tightening.

Overall, the installation of the FOX Performance Series Shocks was straightforward.  The front shocks were definitely more of a challenge to replace. Having some mechanical skill and the right tools will make all the difference.

Replacing all four shocks took under 1.5 hours.


Since these new shocks are longer than the old ones (1.5 - 3 inches longer), it was recommended by ORW that we extend the brake lines on the Jeep Wrangler JK to avoid them over stretching, or worse, tearing off completely. We really didn’t want to deal with no brakes on the trail, so the advice was taken very seriously.

There are two ways to go about this: 1). The brake lines can be extended by relocating the factory lines with brackets from TeraFlex; 2) Longer brake lines can be installed to replace the factory lines. Brian opted for the longer brake lines, gaining some brake performance in the process. We used TeraFlex Steel Braided Extended Brake Lines, which will keep the Jeep’s brakes working during extreme suspension droop and articulation on the trail.

The following TeraFlex Extended Steel Braided Brake Lines were used on our Jeep Wrangler JK Unlimited with 2.5-inch suspension lift:

Part# 4353310 – JK 26” Front (pair)
Part# 4350310 – JK 30” Rear (pair)

The steel braided construction of the TeraFlex brake lines (bottom) gives them an extra layer of protection over the factory rubber lines (top). This can be advantageous when traveling on trails with sharp rocks, branches, logs, ice and other protruding objects.

Steel braided brake lines are heavily used in motorsports and racing applications. They have a much more true pedal-to-brake feel than factory rubber hoses. The performance advantage is felt when brakes become hot on curvy roads. Hot brake fluid makes standard rubber brake lines expand under stress—resulting in a squishy brake pedal and poor braking performance. The steel braided layer found on the TeraFlex brake lines helps keep brake lines from expanding under stress and heat, sending more fluid to the calipers where brake force is needed.

Installation of new brake lines does require opening the brake system. If you’re not familiar doing brake jobs or bleeding air out of the system, this job is best left to a professional. You need good working brakes to off-road another day.


As soon as the Jeep was ready to drive, we went out for a quick spin in the San Diego backcountry. The Jeep felt and rode much smoother with these new FOX Performance Series Shocks. They also look great! Pushing through on some curvy two-lane highway made the Jeep feel like it was on rails. 

Pot holes were soaked up, and we never experienced the infamous “Death Wobble” many Jeep Wrangler JKs have been experiencing as of late, even with 35-inch tires and a 2.5-inch lift. We got to drive on some washboard road, which really crystallized the fact that the FOX Performance Series Shocks truly ride smoother than the old shocks right out of the box.

FOX’s Performance Series delivers a quality shock absorber that can haul the mail on dirt yet handles great on the highway.

We later took the Jeep out to the Colorado Desert to further test the FOX Performance Series Shocks. Blasting over washes and choppy dirt roads, the FOX shocks soaked up the hits and kept the driver in control, even at higher Jeep speeds. On rocky terrain the FOX Performance Series Shocks also did well. The Jeep climbed over rocks and tackled off-camber terrain with surefooted attitude.

The added shock length gained with these new shocks (Front: 3.5 in., Rear: 1.5 in.) helped increase travel and articulation on technical terrain. We also noticed that with the front sway bar disconnected, the FOX shocks moved even more, giving the front axle further reach. Thanks to longer TeraFlex brake lines, our friend Brian was able to confidently let his Jeep’s suspension move around and flex. Everything just seemed to work really well together, making this Jeep Wrangler JK Unlimited even more fun to drive on all terrain.

The FOX Performance Series Shocks offer great value for the performance-minded Jeep owner looking to get dirty without breaking the bank. Brian has logged almost 1,000 miles on his new set of FOX Performance Series Shocks over the last few months and is still very happy with them. He assures us that these shocks ride and handle much better than the old ones. 


FOX Shox


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