The stock heavy-steel pickup bed didn't fit into our long-term plans for the Trails Less Traveled Tacoma. We needed to mount longer rear shocks, store additional fuel and carry a full size spare tire. Our long-term plans also include relocating the radiator and two batteries to the rear of the truck for better weight distribution. We came to realize that there would be more compromises in keeping the stock bed than in removing it entirely; so we designed a lightweight utility bed-cage to make better use of the space.

Many heavily modified trucks are well equipped to run desert racecourses, but this project vehicle will remain our daily-driver. Traveling for extended periods of time also means that we need to be able to carry a substantial load over long distances on and off-road. In planning to build a utility bed-cage to suit our needs, we had to consider the intended use of the vehicle and the type/amount of gear that we planned to carry. We made a list of all our design requirements and then began making adjustments to incorporate all the features that seemed incompatible before we started.

UTILITY BED-CAGE GOALS

• Uncompromised Suspension Design

• Accommodate 18-23 gallon fuel cell

• Carry at least one 35" Spare Tire

• Rear-Mounted Radiator

• Dual Rear-Mounted Batteries

• Carry Assorted Tools

• Carry Spare Parts

• Carry 48 Hi-Lift Jack

• Run With/Without Bedsides

• Carry Two Full-Sized Dirt Bikes

• Carry Two Mountain Bikes

• Carry One 75lb Dog

• Carry 50-70 quart Cooler

• Carry Misc. Riding/Camping/Outdoor Gear

BLUEPRINTING

The suspension and fabrication work on this truck has been completed in stages, but everything was designed before any of the work began. To read more about the rear suspension, click here.

We started with the rear suspension, knowing that the 40.5" long (extended length) Sway-A-Way shocks would eat into valuable bed-space. Wheel-travel was our primary concern, but as we worked with the physical dimensions of these parts we tried to anticipate how they would fit into the bigger picture. The final location of the upper shock-mounts allow for an oversized aluminum radiator to be mounted in the framework, and the crossbar is set back at the perfect distance from the main hoop to cradle the front tire of a mountain bike or dirt bike.

The main roll-cage hoop is mounted behind the cab because there is very little headroom inside the standard-cab truck already. It follows the lines of the cab closely, and is positioned so that we can eventually pierce through the sheet metal above the rear window to run 1.75" tubing down the A-pillar. The main hoop is made of 1.75"x.120 DOM tubing. A 1.5"x.090 horizontal crossbar is located at the height of the bedrail, and a 1.5"x.090 diagonal brace triangulates the structure from the high driver's side corner to the passenger's side frame-rail. The rest of the bed-cage is an assortment of 1.75 & 1.5" tubing used to triangulate and strengthen the chassis.

The new spare tire mount will accommodate up to a 35" spare tire with better ground clearance than a stock truck. This was accomplished by creating a new rear floor-pan 7" above the frame-rails (about 6" higher than the stock bed floor), using a combination of 1x.120 tubing and 1/8 cold-rolled plate to remount the spare tire and provide a flat 35x37 area for cargo. We are reusing the stock cable-operated spare tire mount.

The bedside mounts were fabricated using a combination of .75x.090 square tubing for the bedrail mount, 7/8x.090 tubing for the supporting tube-work, and 1/8" cold-rolled plate for the body-mounting tabs. They were designed to be lightweight and unobtrusive when the bedsides are removed (for rock crawling, etc.). They are also very easy to repair or replace when they get damaged.

UTILITY BED-CAGE

Toyota Tacoma's use six mounts to fasten the bed to the frame. These pictures show the front, middle and rear driver's-side bed mounts respectively. The stock bed mounts don't need to be removed, but they can never be used to re-mount the stock bed since the utility bed-cage is a permanent modification (welded directly to the frame-rails). We cut off the four forward mounts where they were welded to the frame-rails and then ground the welds down (the two rear mounts are just holes in the frame-rails).

We drove the Tacoma back to Rock Star Trux, in San Jose CA, where Chris had already fabricated the upper shock mounts and installed our 62" Deaver leaf-springs. Chris is shown here pinpointing the location of the cross brace for the main hoop before he sections and then welds the tubes into place. The main hoop was assembled on the concrete workshop floor because it is a level surface, and also allowed Chris to get 100% welds around all of the tube junctions.

Chris then formed & welded this plate to the frame-rail where the main hoop will be mounted. The additional material provides a solid foundation for the main hoop and in the event of an impact the gussets will help to spread the forces generated over the entire area of the plate instead of just the welded area around the diameter of the tube.

We verified the measurements between the main hoop and the upper shock mounts before tack-welding anything into place. Then we laid in the rest of the tubing like a game of connect-the-dots, and then finish-welded the entire cage after double-checking all of our measurements.

We live in a coastal climate and built our bed-cage over the course of a few weeks, so it was important to primer & paint our work to prevent the material from rusting. The tubing that is painted black was the first stage completed, the material in primer was more recent progress, and the bare metal is work in progress.

This is the finished perimeter/structural assembly of the utility bed-cage. We are still planning to install a license plate, LED taillights, and a receiver hitch in the rear bumper. By mounting the lights and license plate directly to the bed-cage, we will be able to remove the bedsides for rock crawling and still have a street legal vehicle.

This close up of the rear bumper shows some of the finishing work. We added extra material to this high-impact zone by capping and gusseting the bumper with 3/16" cold-rolled plate. We will add additional gusseting when we mount the taillights and integrate a 2" receiver hitch. We have made every attempt to find a balance between strength and weight, and have really tried to use materials to their potential.

FIBERGLASS BEDSIDE MOUNTS

After the structural work was completed, we had to fabricate and install the mounts for the bedsides. The .75"x.090 square tube that runs back horizontally from the cab along the outside of the utility bed-cage is the main support for the flared fiberglass bedside. Two round pieces of 7/8"x.090 tubing are used to support the rear of the bedrail mount.

In addition to the bedrail support, the bedsides needed to be stabilized with other mounting points. These are the forward wheel-well opening mount (pictured on left) and the rear wheel-well opening mount (pictured on right), made from 7/8"x.090 tubing and 1/8" cold-rolled plate. We chose not to mount the bedsides at the lower corners so that if they bump against something, they can easily flex out of the way.

Here is the completed framework for our utility bed-cage, with the driver's bedside removed to expose the bedside mounts, spare tire mount and interior bed-space. Storage is more compartmentalized than an open 5x6" pickup bed, but the space we have created can be used to securely mount and carry all of the things that we'll need to travel with.

Here is a detail shot from the underside of the passenger?s side fiberglass bedside. We are not currently running any type of mud-flaps or interior wheel-wells, but we are working on something to keep rocks from flying up into the cab and rear window.

SPARE TIRE MOUNT

Once the bedsides were securely mounted, the next step was to mount the spare tire. We chose to re-use the factory spare tire mounting-hardware because it will allow us to easily lower the spare out from the underside of the Tacoma without requiring any cargo to be unloaded from the bed. We also raised the factory mounting location in order to allow us to fit a full-size spare and at the same time increase ground clearance. Since we intend to use the utility bed to carry dirt bikes and other heavy loads, we used 1"x.120 wall round tubing intersecting a fabricated steel box made of 1/8" cold-rolled plate.

The 33x10.5" tire (shown here) tucks nicely above the frame-rail. For comparison, a spare 35 tire would sit higher up in our new location than a 31" spare tire on a stock truck.

INTERIOR BED PANELS

We have riveted thin aluminum panels in-place (shown here) to allow us to utilize the basic layout of the utility bed-cage while we continue to build the vehicle in stages. The interior bed panels can easily be reconfigured to suit our needs through the life of the project, as we make changes and incorporate new upgrades. The enclosed forward section of the bed was designed to clear the stock gas tank, but the floor of that section can easily be replaced when we install an 18-23 gallon race-legal fuel cell to give the vehicle extended range and help with weight distribution. The shock tower is positioned low enough, and at the right distance back from the main hoop to fit the gap between the forks and the radiator of an average sized dirt bike, although we haven?t reinforced the floor in those areas yet. The utility bed-cage is encouraging, but there is still a lot of work ahead of us if we are going to accomplish all of our original goals.

Contact Information:

Rock Star Trux
www.rockstartrux.com

408.295.5055

573 Julian Street
San Jose, CA 95110

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