BUMMER!

Readers of Kit Car are accustomed to seeing the flowing lines of a Cobra, the immortal beauty of a classic Bugatti, and the powerful bulges of a Lister or D-Jag replica. Not this time. Instead, we present you with something that has the flowing lines of a brick and the aerodynamic characteristics to match. It places function ahead of style. It’s called a Bummer.

The Bummer comes from Tatonka Products—a Salt Lake City, Utah, group that has long specialized in building custom fiberglass molds for the industry. It isn’t clear from what deep, dark recess of owner Richard Tolbert’s mind the Bummer idea came, but Tatonka has sold nearly 120 Bummer kits during the past few years and shows no sign of slowing down.

The utility-type bodies are designed for pickup and SUV chassis. Tolbert says it’s the ultimate way of recycling a truck that runs good and looks bad. The resemblance to the military Hum-vee is obvious, but the dimensions and proportions are completely different. The Bummer kit will fit most Chevy, Dodge, and Ford pickup chassis, as well as many full-size SUV chassis such as the Suburban, the Blazer, the Ramcharger, and the Bronco. Tatonka is currently working on a scaled-down kit to fit the GM S-10 chassis and other smaller trucks.

The Bummer can be configured as a short- or long-wheelbase, two-door pickup or a four-door people mover. At least one Bummer is being built on a 164-inch-wheelbase, crew-cab chassis and will have six doors. The body is only slightly wider than the original truck, but it utilizes more interior space due to its boxy proportions. As a result, four-across seating can be accomplished. This allows the two-door pickups to seat four, the four-door to seat eight, and the six-door to seat 12. Most Bummers are built as ragtops, but a hardtop will soon be available for fully enclosed comfort. Hard or soft doors are available according to taste. In the case of two-doors, Jeep Wrangler doors can be used.

The conversion of pickups is relatively simple and straightforward. No serious special tools are needed. Blazers, Suburbans, and other SUVs with rear-mounted fuel tanks are a bit more difficult. The necessary chassis modifications at the back are complicated by the fuel tank. One relatively easy cure is the mounting of pickup-type saddle tanks. Other ideas include a custom tank or alterations to the kit that leave room for the original fuel tank. Most novices report being able to complete a standard installation on a pickup in 80-100 hours. Some owners have reported being able to get the body installed over a weekend with a little “armstrong” help.

The beauty of the Bummer conversion is that it automatically improves the performance of the vehicle on and off the road with no mechanical mods. The new body has wheelwells that allow the installation of tires up to 38 inches tall with no suspension lift. The loss of weight improves overall performance and increases drivetrain durability. The option of bigger tires increases clearance and adds traction. The bigger tires may require a gear-ratio change.

In the case of pickups—especially ¾-ton and 1-ton units—the loss of weight results in a vehicle that may be much oversprung. The softer-riding SUVs and ½-ton pickups are less affected. The best idea is to figure on derating the springs as a part of the conversion. Spring rates similar to light-duty, ½-ton Blazers or Suburbans seem about right for most Bummers.

The Bummer featured here is called the Bum-V. It was built on an ’83 Blazer diesel chassis and configured as a short pickup with sideboards. As a Blazer, it had already been heavily modified for trail performance, but the installation of the Bummer kit greatly enhanced the vehicle’s performance. As an overbuilt, heavily modified Scottsdale Blazer, it weighed nearly 6,400 pounds. When put on the scales after the conversion, the Bum-V weighed in at just 3,880 pounds. That’s lighter than some Jeeps, and it was enough to cut a full 2 seconds off the diesel Blazer’s best 0-60 time of 14.4 seconds.

New front, rear, and center crossmembers have really tightened up the chassis, both on and off the highway. It holds a line better in turns and, surprisingly, significant chassis flex on difficult trails—a notorious GM trademark that eventually results in cracks—has been much reduced. As expected, the Bum-V is a bit over-sprung now, but a lighter set of custom springs is in the offing. There’s now room to replace the 35x12.50-15 tires that look too small, with some larger 37- or 38-inch meats. With the loss of weight, the drivetrain can now handle the extra rubber.

On the trail, the loss of weight has translated into better performance. The vehicle climbs easier, descends more slowly, and the torque converter feels tighter. Since converter stall speed is partly dependent on vehicle weight, less weight has the effect of lowering the stall speed. Flash stall (the peak, full-throttle “launch” rpm) has dropped 250-350 rpm. Most of the weight was lost in the rear and the truck is now a bit more nose heavy. That has translated into more pull from the front end on hard climbs.

Building the Bum-V was more difficult than a gasoline-powered-pickup conversion for two reasons: the aforementioned fuel-tank difficulties and the diesel engine. We talked about the fuel tank, but the dimensions of the diesel and its massive radiator forced Tatonka to abandon the production kit and go completely custom for the radiator mounting. The body also had to be moved forward slightly. Fortunately, there is considerable leeway to position the body as needed to cover unforeseen problems.

The Tatonka kit is available in a bare-bones form or with lots of extras such as a rollcage, doors, and top. There is an almost infinite variety of accessories that can be added and the choices in outfitting are numerous. Some owners have outfitted Bummers quite luxuriously, while others build them in a spartan “hose-out” form. Because it has built many Bummers in house, Tatonka can supply useful information on what works and what doesn’t.

In four-wheeling circles, the Bummer is a head turner. Wise chiropractors will follow you around, dispensing business cards and drumming up whiplash business. Park it in the grocery store parking lot and you’ll find five people ogling when you come back out. But, total functionality has a beauty all its own.