Although our initial tests...
Although our initial tests were conducted in the Hammers, we have continued flexing the Universal Stinger over every big rock we can find. Here, some hecklers look on as the Stinger helps the Bee negotiate the Little Sluice on the Rubicon Trail.
In the March '06 issue, we brought you the full story on Nth Degree Mobility's long-arm suspension for Jeep TJs. This suspension is fast becoming the suspension to have under your hard-core TJ, allowing a street-driven Jeep to play with rock buggies. One of the unique components of the kit that plays a big role in its performance is the Stinger. The Stinger is a torque arm that replaces the upper control arms in a TJ's rear suspension. It distributes torque evenly to the center of the chassis and does away with several of the TJ's weird handling traits.
Now Nth Degree has designed a larger, Universal Stinger that will fit onto aftermarket high-pinion Dana 60-based rear axles. So if you've upgraded your TJ with an Nth suspension, and are now considering beefier axles, you can easily install the Stinger. Even better, if you've got a 60 of any brand under whatever your rock rig is, you can now easily install a Stinger and enjoy the traction and handling benefits it affords.
My old "Killer Bee" flatfender has been in my possession for 31 years now. The only parts left that go with the '60 Willys serial number I've held title to since 1975 are the two main framerails and the tailgate. Some say I've gone too far and it's just another rock buggy these days ... well, so be it. A vehicle that's spent a long life on big rocks just kinda ends up that way. The Bee has been, and forever will be, evolving, and its latest trick is an Nth Degree Stinger attached to its Dynatrac ProRock rear axle.
This was the first raw prototype...
This was the first raw prototype as delivered from Nth Degree. On the left is the production TJ-sized shackle, which proved to be too wimpy for V-8 torque and 60-sized axles. It has since been upgraded with a larger design that incorporates a gusset and a centered Heim joint. The main bracket captures and surrounds the pinion snout through the hole in the front, while the sides reach back and attach to the axletubes via U-bolts. Further attachment to the diff is provided via a weld-on plate that attaches to the Dynatrac-supplied diff bridge shown at the far right.
I first installed coil springs and my self-designed torque arm/three-link/Panhard-bar rear suspension in 1995. At that time, I employed a centered rear torque arm that worked using the same principles as Nth's Stinger, but it was much cruder and a lot noisier. The Jeep worked great, however, and this setup was even used in the earliest rockcrawling competitions. A few years ago, I went away from this design and built a more conventional four-link wishbone-style rear-link setup. For years, I fought this design as I found the Jeep struggled more on obstacles that it used to walk over. It tended to lift front tires more as the torque load seemed to be directed at one framerail or the other.
When Jim Frens, owner and engineer of Nth Degree products, asked me if I wanted to prototype his new Universal Stinger on the Bee, I jumped at the chance. Having 'wheeled his designs on various TJs, I'm a firm believer in his chassis knowledge. If I have to employ the talent of this former Jeep engineer over my backyard "engineering" to make the old Bee sting again, I'm all over it.
The installation of the Stinger to the Dynatrac ProRock is an easy fit and can be done with the axle under the rig. The design, if a bit chunky (the production units have lightening holes), is beefy and includes a useful skidplate for the rear U-joint. I had to fabricate a forward mount for the shackle (see photos) and a Panhard (track) bar also needed to be fabricated and employed.
The first test trip was a weeklong thrash fest in the Hammers under the curious eyes of some of the most well known and oldest (read: been around the longest) rockcrawlers in the sport. I can't say the Stinger came through unscathed, as we had some strength issues with the original, TJ-based production shackle. A beefier, gusseted one has since taken its place with no more issues. Despite this minor prototype issue, the traction and handling virtues of again employing a center torque arm to the Bee brought back its days-of-old capability. The function of Nth's Universal Stinger design is well up to any flexy twisting the Hammers can offer, and all of the torque that the Bee's ZZ4, 4.3 Atlas and 40-inch Iroks could muster couldn't destroy it.
 Installed on the Dynatrac...  Installed on the Dynatrac ProRock 60, the Stinger looks large, but fitting. The production units, which will be available by the time you read this, will have large, lightening holes in the two sides that reach back to the diff tubes. The useful U-joint guard also helps clamp the pinion snout firmly in the main bracket mounting hole. The Stinger arm itself is attached to the bracket via two vertical Heim joints that allow some flex and provide for pinion angle adjustment. |  In this ant's-eye view, you...  In this ant's-eye view, you can see how the Stinger mounts pretty much in the center of the axle and runs parallel to the driveshaft. Being rigidly attached to the axlehousing causes it to become an extended arm that transmits the axle's torque twist directly into the center of the chassis via the shackle mount. The shackle allows for fore and aft suspension movement and provides a quiet, cushioned mount. A Heim joint attaches the Stinger arm to the shackle. Its sole purpose is to allow the arm to twist with the axle's articulation. Part of the beauty of the Nth design is that every part only has one job to do, so there is no binding or fighting of components during flex. |  When installing the Stinger...  When installing the Stinger in a universal application like on the Bee, there is some fabrication that needs to be done. A mount like this will need to be installed in the center of the frame, up near the transfer case and alongside the forward U-joint for the attachment of the shackle. We originally used a rubber bushing, but have since switched to polyurethane for better durability. |
 The design of the Stinger...  The design of the Stinger is such that everything is tucked up out of the way and doesn't affect the good clearance characteristics of a high-pinion 60. |  Since the Stinger is a three-link...  Since the Stinger is a three-link design (two lower control arms plus the Stinger), a Panhard (track) bar must be employed to locate the axle laterally. Depending on the application, this may have to be fabricated as well. Jeep TJs already have a track bar, but since the Bee had a wishbone design before the Stinger, brackets and a 'bar needed to be installed. On the axle side (at left) I was able to use a modified Nth Degree TJ bracket. Always try to make a Panhard bar as long as possible and parallel to the axle at ride height. |  A week of hard-core rockcrawling...  A week of hard-core rockcrawling on the Hammer trails in Southern California provided a tough testing ground for the Universal Stinger. We found a weak spot in the shackle which has been addressed, and a Universal Stinger should be available for your application by the time you read this. |