Bob Chandler rode his passion for four-wheel-drive trucks into a successful career.

Spotting an opportunity, he opened a lucrative truck parts and accessories business — and stepped on the gas in automotive design and technology.

Chandler's desire to build the biggest and baddest four-wheel-drive truck led him to make the first monster truck, called Bigfoot. His drive led to the creation of a new category of motor sports and arena entertainment that delights millions of adults and children every year.

Chandler was ahead of his time when it came to four-wheel-drive trucks. There were few on the road when he got his first — a 1975 Ford F-250 pickup truck — in 1974.

"When I bought my first four-wheel-drive truck here in St. Louis, the only other four-wheel-drive trucks around belonged to utility companies," Chandler told IBD. "There were very few four-wheel-drive trucks on the road and none of them were for personal use, which is what I bought it for."

Chandler enjoyed taking his truck off-road for recreation. He particularly liked driving through gravel-bottom rivers in southern Missouri.

He saw the potential for the market and soon opened a shop to sell parts and accessories for truck enthusiasts. To drum up business for his Midwest 4-Wheel Drive Center in Hazelwood, Mo., he souped up his truck with parts from his shop and used it as a rolling billboard.

Step On It

Called Bigfoot, because of Chandler's lead foot behind the wheel, the truck featured big tires, big axles, big suspension and a high-performance engine. Rear steering was another popular innovation. Steering on the rear axle let the truck make tight turns and keep driving when the front axle broke.

Bigfoot accomplished its goal of drawing business to the store. But the truck proved to be an attraction of its own. "It was good for the business," he said. "It was an advertising tool at first, but it went wild."

Chandler's Bigfoot performed at its first paid event, a Denver car show, in 1979. Exhibition truck pulls in arenas and stadiums soon followed. Magazines featured Bigfoot, and its popularity sped ahead.

In April 1981, as a lark, Chandler drove Bigfoot over a couple of junk cars in a field while a friend videotaped the stunt.

With its huge tires and beefy build, Bigfoot drove over the cars like they were cardboard, Chandler says.

When Chandler began playing the video in his shop, a man promoting a motor sports event in Columbia, Mo., asked him to repeat the car-crush stunt in front of a crowd. Chandler was reluctant at first because of the destructive image it would convey, but he eventually agreed to perform at the event in April 1982. The crowd went wild, and Bigfoot was suddenly in big demand for similar events.

Chandler says he hates the image of monster trucks crushing cars, but realizes the action put the vehicles on the map. He also knows that if he didn't do it, someone else would.

These days Chandler, 65, is focused on organizing a legitimate racing series for monster trucks. He leaves the destructive spectacle of car crushing to others, like Live Nation's Monster Jam tour. Last year, Monster Jam alone sold 3 million tickets to 250 events worldwide.

Chandler hopes to have a few test races this year before the official series starts next year. Organizers are working on straight-line, figure eight and U-shaped tracks, he says. "It's the future of monster trucks."

People are going to get bored with events focused on destruction, he says. Racing involves more driver skill and the thrill of competition. Bigfoot team trucks have won 18 titles from racing tournaments.

Chandler has built 17 Bigfoot trucks, each one an improvement. Current monster trucks weigh 10,000 pounds, or 5 tons. They're 10 feet high and 12 feet wide. They use 1,500-horsepower engines.

And those tires — 66 inches high. They're adapted from ones used on farm tractors that spread fertilizer.

Chandler prides himself on the fact that each of his trucks is different. He continues tweaking on the engineering side. "We keep building new trucks and we don't copy. Now it'd be easier to copy a truck, but then you're not moving forward. And if you're not moving forward, I think you're going backward," he told author Bill Geist for his 1994 book "Monster Trucks & Hair-In-A-Can: Who Says America Doesn't Make Anything Anymore?"

Chandler says he learned about automotive engineering "hands-on, trial and error, what they call the school of hard knocks."

He faced a lot of skepticism from auto mechanics and engineers as he tried to make his trucks bigger and stronger. That only motivated him to prove them wrong. "That just turned me on. I found a way to make it work," he said. "Once I had a truck that was bigger than anyone else's, I wanted to go further."

He'd put bigger tires on his trucks, but would break axles. He'd put stronger axles on them, but would need a more powerful engine. It took four years to perfect the original monster truck design, he says.

Those early monster trucks were so heavy and rough riding, several drivers were seriously injured doing jumps and in crashes. That's when Chandler turned his attention to safety and overhauling the design of monster trucks.

He learned about AutoCAD, a software program for computer-aided design, and realized that was the way to go. He also saw a drawing of a tube chassis for a drag-racing car and thought he could adapt that to a new monster truck frame.

With the computer program, he designed a tube chassis frame that would make the trucks lighter and faster. He also came up with 18 to 20 inches of suspension travel rather than the prior 6 inches. That made the trucks easier on the drivers. The more suspension travel, the more ability to absorb shocks.

Building trucks in digital form was quicker and easier than building them with metal. Chandler could try out new ideas without wasting actual parts and gear.

Always interested in learning and trying new things, Chandler has moved beyond AutoCAD for his next monster truck design. For the new design, he's using a computer simulation program called finite element analysis. This lets him see how much stress is put on every piece of pipe in the truck chassis.

Banged Up

Most of his trucks are over 10 years old and beat up, he says. "I don't have a straight frame left." They all have kinks in their frames and have been repeatedly patched up.

With the new design, he hopes to come up with a monster truck that lasts longer and can handle more abuse. The design process will take several more months. A new truck based on that design would take an additional six months. "When people say it can't be done, for some reason I just want to do it," Chandler said. "I don't like following people. I like doing things different."

Chandler, who serves as chief executive of Bigfoot 4x4 Inc., has no plans to retire. He says he enjoys what he's doing too much.

"Trucks have been my life," he said. Chandler drove a pickup truck in high school and used a pickup for about 15 years in the construction trade before he got into the four-wheel-drive truck business.

Chandler, who grew up in the St. Louis area, entered the Missouri Sports Hall of Fame last year.

BY PATRICK SEITZ.