The state-of-the-art in monster truck suspensions, circa 1990, on Bigfoot 9: tube chassis, cantilever suspension with gas-charged shocks, ZF axles with internal wet brakes, and planetary gears. This Bigfoot was lost in Brazil in 1998 after a customs dispute.
4WOR: How did car crushing come about?
BC: I saw a TV show once where they made a big deal of a truck that put its front tires on a car that was more than half buried in the mud. I told myself Bigfoot could drive over that car. I later told Jim Kramer I would like to try driving over cars, and he set it up with one of his friends who owned a farm.
Driving over the cars was easy. The first time, we put a bale of hay by the trunk of the first car to get the tires up. I did my first car crush in 1981. I'm not sure if that was the very first car crush or not.
I videotaped the car crush and played the tape in my shop. A promoter saw the video and wanted me to do it again in front of a crowd. I balked at the idea because Marilyn, my wife, and I thought it was too destructive. But the kids loved the video, so we decided to do it in front of a crowd in Jefferson City [Missouri] a few months later. I was shocked at the reaction from the crowd. They went nuts.
4WOR: Why do you think they liked it so much?
BC: Because they were seeing the same pickup that their dad or their uncle owned, but on steroids. It was huge. Kids like big things-tractors, big rigs, fire trucks. Adults just seem to like destructive things, whether it's car crashes or buildings being blown up. And, everybody's been stuck in traffic and wished they could drive over the cars in front of them. Even I do that.
Bigfoot technology took a giant leap-pun intended-with the introduction of the cantilever suspension on Bigfoot 8 in 1989. | 
On the right is "Star" Bigfoot (Bigfoot 14), currently one of many Bigfoot trucks touring the U.S. |
The Bigfoot team notched its 20th championship in April 2007, when Dan Runte in the Summit Racing Bigfoot (Bigfoot 15) won Checkered Flag Productions' '07 Monster Truck Winter Nationals. | |
4WOR: How did the subsequent Bigfoot trucks come about?
BC: Bigfoot 1 was being used all the time, so we didn't have much time to do much with it in the way of improvements. So we built a second truck. We made all the modifications to it, including the 66-inch tires, and that's when we realized those tires weren't going to work with the 2 1/2-ton axles. So we went to the 5-ton military axles.
The bigger tires meant a bigger overall gear ratio, so we had to go with a lower transfer case to get the thing to run. Then the engine wasn't strong enough, so we had to add more horsepower. It was a vicious cycle-bigger tires, axles too small, bigger axles, not enough power, then you start ripping out transfer cases and transmissions. It just went round and round and round.
That's when we found the planetaries, which put a reduction right at the wheels. Today we run a 6.2:1 planetary ratio; back then the military axles had 3:1 ratios. The planetaries were easier on everything. Axleshafts only had to be the size of a 1-ton truck because everything reduces at the wheel. That was the salvation for monster trucks.