Project Trailhugger Hummer H3 Alpha Suspension - Part 7

Here at Four Wheeler we like Light Racing JounceShocks so much we've installed them on several project rigs. 'Con Artist, Killer Bee, and our Nismo Frontier are some of the recipients of these extraordinary little devices, and we've been very impressed with the results. This month, we install them on our project Trailhugger H3 Alpha.

If you're not familiar with JounceShocks, here's the short version: These devices are basically air springs with damping control that replace the stock bumpstops on your vehicle. Devices like these have been used in the off-road racing scene since the late '80s, but only recently have found their way into the mainstream off-highway market. So what is the benefit? Well, as a supplemental suspension device typically utilized during the last third of suspension travel, JounceShocks provide vastly improved bottoming protection and substantial improvements in gross vehicle motion. In other words, they can do all kinds of tricks that a piece of rubber or urethane can't. As a bonus, they're externally adjustable for compression and rebound, nitrogen and oil fill adjustable, and fully rebuildable.

1. For reference, here are all of the stock parts that we removed to install the JounceShocks. Where did they come from? Read on.

1. For reference, here are all of the stock parts that we removed to install the JounceSho

As you'll recall, our plan for Trailhugger includes keeping the suspension height stock. To some this may seem like a radical decision, but our goal is to explore ways to preserve, and improve, the rig's excellent handling and ride, both on- and off-highway, as well as retain our rig's decent mpg numbers. After all, Trailhugger is a daily driver. With that said, we planned on integrating minimal suspension mods that provide maximum results. In Part 2 (Sept. '08), we installed a set of rugged Rod Hall Racing piggyback shocks. Now, with the addition of these JounceShocks our suspension modifications are complete.

The kit for our H3 Alpha came to us from Light Racing with everything needed to transform the ride and handling. We pointed Trailhugger to Attitude Performance in Arlington Heights, Illinois, where owner Matt Dinelli made it happen. Here are the highlights of this relatively easy install.

2. Light Racing offers universal fit and custom fabricated JounceShock systems. Ours was the latter, so it came with everything needed to complete the install, including front and rear weld-on mounting brackets, a pair of front 1.5-inch-travel JounceShocks, a pair of rear 3-inch-travel JounceShocks, a pair of rear hit pads with fasteners, and four domed feet for the JounceShocks. This system is designed to fit a stock-height H3 Alpha.
2. Light Racing offers universal fit and custom fabricated JounceShock systems. Ours was t
3. This is an image of the stock front passenger-side suspension at full droop on a lift. Notice the contact pattern on the lower A-arm made by the factory urethane jounce. The H3 (as well as many GM IFS trucks), is designed so the factory jounce rests on the lower A-arm. The only time the jounce doesn't contact the lower A-arm is when the suspension is unloaded, or drooped.
3. This is an image of the stock front passenger-side suspension at full droop on a lift.
4. The first step to install the new front JounceShocks is to remove the front wheels, stock urethane jounce pads, and front shocks. The torsion bars are then loosened and the halfshafts are covered with a weld-resistant material. The next step, shown here, is to cut off the stock bumpstop brackets. Specific instructions are included with the kit outlining what to remove and what not to remove.
4. The first step to install the new front JounceShocks is to remove the front wheels, sto

5. In preparation for the installation of the Light Racing mounting brackets, the frame surfaces where the stock brackets were removed are ground smooth as shown here.
5. In preparation for the installation of the Light Racing mounting brackets, the frame su
6. Detailed instructions explain, and illustrate, exactly where the JounceShock mounting brackets are to be welded to the framerails. The mounts are tack welded to the frame and the JounceShocks are test-fit to ensure good alignment with the top surface of the lower A-arms.
6. Detailed instructions explain, and illustrate, exactly where the JounceShock mounting b
7. Here's the passenger-side JounceShock bracket after it was welded on. The welds were cleaned up with a wire brush and then each mount was painted to limit corrosion.
7. Here's the passenger-side JounceShock bracket after it was welded on. The welds were cl

8. With the mounts installed, the domed feet were screwed into each JounceShock shaft end using a 1/4-inch pin wrench, and then the cylinder end of each JounceShock was threaded into their respective mounts. The final step was to install the 1/4-20 set screw with a dab of medium-strength thread locker. Here you can see the completed passenger-side assembly. The front end is completed by tightening the torsion bars and reinstalling the shocks and tires.
8. With the mounts installed, the domed feet were screwed into each JounceShock shaft end
9. To install the rear JounceShocks, we began by removing the stock urethane bumpstops and their mounts. The JounceShocks will fit without removing the mounts, but we wanted them out of the way since they would no longer be used.
9. To install the rear JounceShocks, we began by removing the stock urethane bumpstops and
10. After we removed the factory rear jounce brackets, we were surprised to see that the frame area under the brackets hadn't been welded from the factory. Naturally, Dinelli welded each side closed.
10. After we removed the factory rear jounce brackets, we were surprised to see that the f

11. The lower hit pads are the first items to be installed. The new pads are pre-drilled and two provided M8 bolts hold each of them in position. One bolt uses an existing hole in the stock bumpstop hit pad, while the other hole must be drilled.
11. The lower hit pads are the first items to be installed. The new pads are pre-drilled a
12. Mounting the rear brackets is similar to the front. Light Racing provides detailed instructions as to how the brackets should be positioned. After the brackets are tack welded in place, Light Racing recommends temporarily installing the JounceShocks and lowering the vehicle back onto its tires to check for proper alignment of the JounceShock to the hit pads. Here you can see the rear driver-side mount installed and painted.
12. Mounting the rear brackets is similar to the front. Light Racing provides detailed ins
13. Here's how the finished driver-side JounceShock assembly looked when completed. Done!

Bottom Line
The JounceShock kit for our H3 has a suggested street price of $1,451.71. In the world of off-highway mods, this is not an overly expensive figure, but it ain't cheap either. This begs the question: Is it worth it? We say heck yeah. During our initial testdrive on a rough road we drive almost every day, we were blown away at the improvement in handling and ride. Because the design of the H3 IFS positions the lower A-arms against the bumpstops at rest, the addition of the JounceShocks made an instant, dramatic improvement to the ride and handling from the front of the vehicle because they're almost always in use. Now, instead of contacting chunks of urethane during uptravel, the lower A-arms contact the domed feet of the JounceShocks, which pushes the shafts into the bodies, which absorbs the force of the upward traveling suspension in a controlled manner. The rear ride quality has been unaffected in normal driving and we've only seen small signs that the rear JounceShocks have been in contact with the new hit pads. Where they'll increase performance is when the truck is heavily loaded, towing, blasting across rough terrain, or jumping.

We have to admit we were a bit cynical and we expected to have to experiment with the compression and rebound settings of the JounceShocks. Turns out the Light Racing team did a fantastic job and we've been very satisfied with the factory settings. For reference, Light Racing says that the front JounceShock for our application ships with 130 psi and the rear ships with 40 psi.

We did swap out the standard hard-nylon domed feet on the front JounceShocks for a softer material. When the lower A-arms droop and then travel upward to contact the JounceShock, we were hearing a clicking noise. Light Racing says this is normal and is an indication that the JounceShock is being applied. Our personal preference was to eliminate the noise. The softer domed feet may wear a tad faster than the nylon, but we don't mind replacing them once a year or so.

Are there any downsides to the JounceShocks? Not that we can figure. They don't impede suspension travel and they don't hang down or protrude. They just do good things.