Chandler's Bigfoot, Everett Jasmer's USA-1, Fred Shafer and Jack Willman Sr.'s Bear Foot, and Jeff Dane's King Kong. At the time, the largest tires the trucks were running were in diameter. In April 1981, Bob Chandler drove over junked cars in Bigfoot in what is often believed to be the first monster truck to crush cars. Chandler drove Bigfoot over a pair of cars in a field as a test of the truck's ability, and filmed it to use as a promotional tool in his four-wheel drive performance shop. An event promoter saw the video of the car crush and asked Chandler to do it in front of a crowd. Initially hesitant because of the "destructive" image that could be associated with Bigfoot, Chandler eventually agreed. After some smaller shows, Chandler performed the feat in the Pontiac Silverdome in 1982. At this show, Chandler also debuted a new version of Bigfoot with 66-inch tires. At a prior event in the early 1980s, when Bigfoot was still running 48-inch tires, Bob George, one of the owners of a motorsport promotion company named Truck-a-rama – later known as the United States Hot Rod Association (USHRA) – is said to have coined the phrase "monster truck" when referring to Bigfoot. The term "monster truck" became the generic name for all trucks with oversized tires. King Kong and Bear Foot each followed Bigfoot to tires, and soon other monster trucks, such as King Krunch, Maddog, and Virginia Giant were being constructed. These early trucks were built on stock chassis which were heavily reinforced, used leaf spring suspension, a stock body, and heavy axles from military-specification vehicles to support the tires. For most of the early 1980s, monster trucks performed primarily exhibitions as a side show to truck pulling or mud bogging events. In August 1983, Bigfoot and USA-1 competed in the first side-by-side monster truck race, which was filmed for the television show That's Incredible. By 1985 major promoters, such as the USHRA and TNT Motorsports, were racing monster trucks on a regular basis. In 1988, TNT Motorsports created a series to establish the first national championship of monster truck racing; USA-1 and rookie driver Rod Litzau edged out Bigfoot, driven by Rich Hoosier, for the title. In 1988, to standardize rules for truck construction and safety, Bob Chandler, Braden, and George Carpenter formed the Monster Truck Racing Association (MTRA). The MTRA created standard