The 6.5 inches of lift is just what we were after for this project.

We’ve all done it. We decide on an aftermarket suspension for our rig, install it, take it to the street and trails, and then say, “I could easily design a better suspension than that!” Well, that’s exactly what the guys at Iron Rock Off-Road did after experimenting with many different aftermarket suspension components for their Jeep vehicles. Nothing seemed to work for what they were doing with their Jeep Cherokees, so they went to the drawing board to create the Critical Path Long Arm Suspension System.

Here's the Iron Rock Critical Path Suspension we installed on our Cherokee.

Iron Rock Off-Road is relatively new to the Jeep aftermarket scene. However, if you talk to the die-hard northern wheelers from places like Minnesota or the Dakotas, the name Iron Rock Off-Road is synonymous with hard-core four-wheeling and is well respected.  IRO specializes in extremely durable and well-engineered Jeep Cherokee and Grand Cherokee products, and we wanted to know more about them. We researched many aftermarket XJ suspensions, and after thoroughly checking out their totally redesigned 6.5-inch Critical Path System, we felt that looking any further would be a waste of time.  This three-link design is innovative, super stout and provides the kind of jaw-dropping flex that we were after for our Cherokee Project, so we gave IRO a call.

Keeping budget in mind, IRO offers an attractive price of $1,449.99 for this kit on its Web site, www.ironrockoffroad.com. It’s hard to find a complete long-arm suspension for this kind of a value. Compare this price to other long-arm kits for the XJ and you’ll soon find out that the next best offering is over $2,000. Remember, we only spent $450 on this clean little Cherokee, so we feel that $1,449.99 is a safe and smart investment! For a total of around $2,000, we are still at half the price of what the average mid ‘90s XJ sells for, but we are now lifted 6.5 inches!

IRO’s unique Iron Y Lower control arm is the heart of this suspension.

The complete IRO Critical Path system includes 6.5-inch coils, 5.5-inch leaf springs with 1-inch-lift shackles, long, high clearance lower control arms with driver side “Iron Y.” The unique transfer case cross member and control arm mounts consist of a three-piece design, making it a cinch to access your center section of the XJ chassis if needed. In addition to the bolts that secure the lower control arm mounts at the unibody frame, we welded here for extra security and strength. The kit also includes a double sheer track bar mount, adjustable track bar, hydro shocks, stainless-steel brake lines and all necessary Grade 8 hardware to complete the 6.5 inches of lift. IRO also offers several upgrades in the shock department, from basic Nitrogen charged, to 5150 Bilstiens with specific valving.

Removing the transfer case cross member is simple.

Installation was a snap. We actually did the entire job without the aid of a hoist … just jack stands and air tools. We were slightly ahead of the game and made sure to use PB Blaster the week prior to tear down of the old, rusty suspension pieces. After the entire factory suspension was removed, all of the Iron Rock components went together easily; however, we did run into a slight problem with a few of the bolts fitting correctly into the captured nuts on the transfer case cross member. We quickly got past the snag and finished the entire installation in approximately nine hours. Not bad considering how much is actually replaced with new suspension pieces from IRO.

Precise caster adjustment is possible with the large IRO cam. Also notice the double sheer track bar mount.

It is not necessary to remove the factory lower control arm mounts, hence the Critical Path name; however, we chose to spend the extra time to get rid of the low-hanging steel. Lastly, there is only one adjustment point with the Critical Path system, as there are no adjustable control arms. IRO offers them as an option, but we didn’t feel they are really needed. The large adjustable cam that attaches the upper control arm mount on the differential is provided for caster adjustments and works very well – it’s very innovative and easy to adjust on the vehicle. We like this!

We couldn’t wait to get the XJ on the road and trails for some testing, so after the last bolt was tightened to spec, we fired up the 4.0 Liter and hit the pavement. The first thing we noticed was the ride quality. At any speed, we can honestly say that our Critical Path-equipped XJ rides as smooth as our bone-stock 2007 Jeep JK Unlimited. Maybe even better than the JK! It is slightly mushy cornering on road and has some minor body roll, but we attribute this to the softly valved Rough Country Hydro shocks.

The XJ has become our choice as a daily driver and will likely continue to be for a long time to come. On the highway, at speeds in the 60s, we’d say that some tuning is needed. Again, some adjustable or firmer gas-charged shocks might be in order to control body roll. The front sway bar is absolutely mandatory at anything higher than 50 mph but we ditched the rear bar and feel comfortable by doing this, as most XJ owners do. Death Wobble is a common and dreaded occurrence with tall Cherokees, but the IRO double sheer mount and solid stock, adjustable track bar kept all of these problems at bay. We feel confident, safe and stable on any long road trip to one of our favorite trails with this suspension in its current state. Overall, we have no concerns or complaints about its highway ability.

Ample flex is achieved with IRO. Pictured is our Cherokee extended about 3/4 of its flex potential.

The Critical Path Suspension was designed for rocks, and while it is a dream on the street, it’s really at home getting roughed up. This suspension works! Its flex is controlled and predictable … and huge! The three-link front end does not bind thanks to the flex joints and the design of the double sheer track bar mount. The only limit in the front is shock length, but we have more than enough now.

We always lift the rear tire at this trail head entrance.  We usually hit the tree too!)

In the rear, we were worried that a 5.5-inch leaf spring would not flex very well and considered removing a leaf from the pack. After our initial run, it was a surprise to us just how well these springs flexed. Even at the entrance of our favorite “secret trail” in Colorado, it was hard for us to lift a rear tire, where we normally do with leaf springs. While snaking through the trees and rocks, we did find that the front coils like to bow inward on compression and hit the unibody frame. We are currently not running any bump stops, front or rear, as the IRO kit does not include them. The plan for the front is to install a set of Rock Krawler’s adjustable bump stops. This should keep the coils from over compressing and distorting as they do now. Our tire size choice with the 6.5-inch suspension is 35s, and we believe it is a great combination. After heavily trimming in the thin, sheet-metal fenders, we have a perfect fit with no rubbing. We’d guess that 33s would be a better choice with this suspension if you didn’t want to cut the body.

We can weld these Rock Krawler pieces in to adjust our suspension compression in the front.

On the trail, we managed to snap a front u-joint on our first day out but had enough time to get a good feel for the Iron Rock suspension, quickly realizing that it is a high-quality product that is going to make a real name for itself. The high-clearance, long-arm nature of the Critical Path system is suited for daily driving, mild trail duty and hard-core rock crawling. This kit is beefy and assures us that we’ll never need to worry about its strength when dragging it through rocks. The install was a cinch and can be done by any shade-tree installer. The price is right for anyone on a budget needing the performance from  true long-arm suspension. All of these simple ingredients add up to one solid package! We like the Iron Rock Suspension and would chose it again for any XJ project. In fact, Jason, Josh and Darrick, owners of Iron Rock Off Road, are currently working on TJ and JK suspensions as well, and we look forward to checking it all out for our new, bone stock JK. 

The Iron Rock Suspension is something we choose again for any XJ project. Owners Jason, Josh and Darrick are currently working on TJ and JK suspensions as well.

If you want pure performance from a completely bolt on, long arm suspension for your Jeep XJ Cherokee, you’ve got to check out www.ironrockoffroad.com. They’ve got a suspension that won’t leave you saying, “I could build it better.”

Note: When ordering this kit, do not trick yourself into thinking that you will drive your Cherokee at this lift height without the use of a Slip Yoke Eliminator (SYE) kit of some kind. With our NP231Jeep Transfer case, the slip yoke actually pulled so far out of the cone, the splines were no longer engaged properly and it was leaking fluid. Add another $100 to $300 to the cost of your complete suspension system, depending on which SYE you choose. Lastly, along with your SYE, you are also going to need a driveshaft that will mate up with your new output yoke on the rear of the T-Case. The consensus is that, by using a front double cardan driveshaft from a XJ, 4.0 liter, AW4 tranny, you will have trouble- and vibration-free running for years. This is also assuming that you have a rear Dana 44 or 8.25 axle. That’s right! Now run down to the local junk yard and spend $20 on a “new to you” shaft!

IRON ROCK OFF ROAD, INC.
12906 Ventura Court, Suite #6
Shakopee, MN 55379
www.ironrockoffroad.com
Phone: 952/210-7185
FAX: 952/233-8785
Toll Free: 877/919-JEEP