Meet the newest member of Four Wheeler’s project vehicle fleet. The Silver Bullet is an ’07 JK Unlimited that we plan to transform into a nimble trail machine throughout the coming year. The build strategy for this one will adhere to a strict diet of aluminum, chrome-moly, and other feather-light materials to prove the concept that lighter is better in virtually all trail scenarios. Through the use of advanced weight-saving componentry, we’ll show you how to make a 6,000-pound SUV perform like a buggy in the real world.
To kick things off, we’re focusing on the rear portion of the vehicle, highlighting one of the lightest rear bumper and spare-tire carriers that money can buy. The bumper is made by Aberle Off Road, a company that specializes in lightweight bumper systems for Chrysler vehicles. In addition to being lightweight, the Aberle unit is attractive and stout, complete with frame-mounted extraction points and accommodations for securing a full-size spare tire as well as a Hi-Lift Jack and shovel. However, the coolest part about all Aberle bumper products is the fact that each is cast entirely from A356 aluminum alloy right here in the U.S. With a total combined weight of just 120 pounds, it’s significantly lighter than any steel JK bumper/tire carrier we’ve tested. Check the highlights from the installation process as it was performed by Phil Evans of Extreme Gear of Rancho Cordova, California.
Step By Step
Here you can see how the Aberle Off Road rear bumper looks once it is unboxed. Aberle offers it raw as shown, or you can option it with a durable black powdercoat finish for an extra $200.
Looking at it from the side, you can see how deep the bumper is and how robust the casting is surrounding the pivot assembly.
The Aberle swing-out tire carrier consists of one solid part that includes provisions for mounting a Hi-Lift Jack and shovel. Notice the small mounting tabs protruding from the top surface of the swing-out assembly.
From the back side, the strength of the swing-away tire carrier is obvious. Extra webbing stiffens the two main parts of the assembly while gusseting between the two portions provides pathways to help distribute the weight of the spare tire across a greater surface area. This intelligent design is what allows the cast aluminum material to handle the cantilevered weight of a spare tire and wheel.
The three-stage Silver Vein powdercoating requires three individual powder applications and heat cycles to achieve an attractive and durable textured finishes that will not fade or chalk up in direct sunlight
The first step to the installation process is removing the factory bumper. As you can see, the JK frame protrudes well past the OE sheetmetal, providing plenty of structure for any type of rear bumper arrangement. The cast aluminum Aberle unit takes advantage of this and utilizes two boxed mounting brackets with flanged ends that slip inside each framerail. Additionally, each framerail receives one additional exterior reinforcement plate that sandwiches the outside of the frame between the boxed brackets and the reinforcement plate. The system is simple and stout—did we mention easy to install, too?
With the boxed frame brackets secured to the inside of each framerail, the bumper simply slips on as shown.
To attach the bumper to the mounting brackets, four 7⁄16-inch Grade-8 bolts must be installed on each extraction hook. The hooks are made from 316 stainless steel material and sandwich the aluminum bumper between the flanges on the mounting brackets and the base of each hook. The setup is easy to install, thanks to the simple design that includes captured nuts welded to each corner of the frame brackets.
With the bumper installed securely to the chassis of the Jeep, Evans turned his attention to the swing_out tire carrier. The most critical step here is coating the male portion of the spindle with a healthy layer of grease. The tight tolerances between the male and female portions of the pivot assembly make it nearly impossible to marry the two pieces without lubrication.
This is how the swing-out tire carrier looks once it is installed on the bumper.
With the tire carrier installed, the cast aluminum tailgate bracket was next. This unit is also made from cast aluminum and installs directly to the OE tailgate using extension mounting hardware. This bracket serves as the foundation for a linkage system that allows the swing-out to follow the tailgate when the factory latch is used. Here Evans is adjusting one of the two link arms that tie the swing-out carrier to the tailgate.
This photo shows how a Hi-Lift jack fits between the swing-out and the rear window.
The lower end of the carrier features a mounting flange that interlocks with the unique shape of the body of the Hi-Lift jack. Two large wingnuts allow for quick and easy access on the trail. The lower red bar is actually the handle of a shovel, which is stored conveniently below the HI-Lift Jack.
The stainless-steel extraction hooks do not require paint or powdercoating and will remain rust-free for years to come.These hooks are also available in a 958 bronze version, which is said to offer superior strength and corrosion resistance while providing a unique golden brown appearance.
We love the fact that Aberle includes a zerk fitting to lubricate the bronze busing to the pivot assembly.
With the Aberle Off Road rear bumper installed, the rear of the Silver Bullet appears ready for anything. we had the good folks at Champion Powder Coating of Rancho Cordova , California, coat the unit with a special Silver Vien powder coat finish to continue a theme we established on the exterior of the rig.
The Silver Bullet is shown here with a set of Black Rhino Ocotillo 17x9 wheels wrapped with 40x13.50 Goodyear MT/Rs with Kevlar. Thanks to a 4.5-inch Trailmaster suspension system, Metal Cloak’s precision-fitting Hi-Line tube fenders, and some slight trimming, these massive tires provided amply ground clearance while giving our JK that puppy-with-oversized-paws look.