Going Nowhere Fast

Harris was among the first designers to apply formal engineering to road racing back in the early 1960s, and he´s been creating cutting-edge-and sometimes beyond-the-fringe-racecars ever since. His rsum includes stints in Formula One and Indy cars, and his prototype sports cars dominated the erstwhile Can-Am and GTP race series in the 1980s and early '90s.

Yet nothing else is like Baja. "Running at ungodly speeds on such horrible terrain for 1,000 miles is an incredible challenge," Harris says. Most Trophy-Trucks fight the course's punishment with bulk–the trucks often weigh more than three tons and ride on suspension components stout enough to club an elephant to death. But this focus on durability has tended to blind off-road builders to technological developments in other forms of racing. Harris, free of such blinders, can apply his singular knowledge base to the restrictionless Trophy-Truck series in any way he sees fit. "In terms of rules, I have no restraints," he says. "I find that liberating from a technical point of view."

Most Trophy-Trucks run the same basic engine, so there's no major advantage to be found there. (Pflueger Racing uses a 455-cubic-inch all-aluminum Chevy V8 massaged to produce 790 horsepower and 685 pound-feet of torque.) Instead Harris identified three areas where he could make a difference. First, he wanted his truck to be lighter than the competition. Second, he wanted it to handle better. Third, he wanted it to develop better traction. He realized that he could get elements of all three with a single piece of technology: an independent rear suspension.

Solid axles–the single bars that hold the wheels in place–have been around ever since prehistoric man figured out that two wheels were better than one. A few millennia later, automobile designers started attaching the front wheels to the chassis rather than to each other, thereby allowing them to move independently and maintain better contact with the road. But designing an independent rear suspension was complicated by the fact that the rear wheels also had to drive the car. (Trophy-Trucks eschew the weight penalties of four-wheel drive.) As a result, to this day, most of the trucks found on the street and in off-road racing use what's known as a live axle–a solid axle that also directs power to the wheels.

Solid axles are cheap, simple and stout, and they're great on flat, smooth roads. But they don't work so well when the going gets rough because the wheels–yoked together by a single axle–can't adjust independently to bumps, potholes and other variables. In off-road racing, where racers routinely encounter jumps, dips and obstacles that would prompt most motorists to speed-dial AAA, one wheel might be on the ground while the other is off. An independent rear suspension seems like the obvious solution, except that no one's been able to make it work better than a live axle in off-road racing. "To put power down in the desert," Harris says, "you've got to work out the numbers and geometry very carefully."

by John B. Carnett:  John B. Carnett

Up until now, no Trophy-Truck with an independent rear suspension has been able to accommodate more than 22 inches of wheel travel. Going into this project, Harris decided that 30 inches was the minimum acceptable. To achieve this goal, he had to make the half-shafts–the components that route power from the differential to the wheels–as long as possible. This meant creating special wheels from scratch and designing a differential case that he calls "the most complicated drawing I've ever done." Ninety hours of programming time were spent setting up the machine that would mill it out of aluminum billet. This was not inexpensive, but Pflueger made the investment. "Because I knew that if I didn't build it," he says with a smile, "somebody else would."