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Project Trailhugger Hummer H3 Alpha Suspension- Shock Jock

Part 7: Light Racing JounceShocks

Ken BrubakerPhotographer, WriterDavid BrubakerPhotographer

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.

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.

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.