Today, supercross is huge. A nationwide series of 17 races draws tens of thousands of fans almost every Saturday night from January through May, and the racers are rock stars earning millions of dollars per year. So lucrative is indoor racing that some top riders don't even bother to compete in the outdoor nationals anymore.
But in 1972, motocross was a relatively new sport that was exploding in popularity in the wake of Bruce Brown's epic film, On Any Sunday. Into this scenario came a bold experiment: bringing motocross into a stadium. The inaugural Superbowl of Motocross at the Los Angeles Coliseum would not only have lasting repercussions, but had perhaps the greatest fairytale ending of any race in the sport's history.
In 1967, in an effort to promote motocross racing in the U.S., Husqvarna importer Edison Dye created the Inter-Am Series to lure the top European talent to America during the off-season. This was a time of complete and utter European domination.
 |  In 1972 it seemed crazy to...  In 1972 it seemed crazy to lay out a motocross track in a stadium, but the idea caught on. Future World Champion Brad Lackey gets the hang of it in practice. |  No team orders here: American...  No team orders here: American Jimmy Weinert (66) puts a classic block pass on his Swedish Yamaha teammate Torsten Hallman. |
Against this backdrop, a young kid from Santee, California, had perhaps the greatest day any motocross fan could ever ask for. Racing locally in one of the first Inter-Am events, the European stars found their way to Marty Tripes' house for dinner.
European riders such as Hakan...
European riders such as Hakan Andersson dominated motocross in the '70s, so tens of thousands of fans flocked to the L.A. Coliseum to watch them race.
"The Europeans didn't like the food here very much, so my dad invited all these guys over to my house for my mom's home-cooked dinner," Tripes recalls. "Here I was, 11 years old, with the world's top motocross riders in my backyard! I remember asking [250cc World Champion] Joel Robert how to ride down the big downhill at Saddleback Park." That evening certainly made an impression on the young American, and he dedicated himself to becoming the best motocross racer he could. Soon, he was to experience European motocross firsthand.
"I learned a lot the first time I went to Europe," Tripes continues. "It was a national race in Prague, Czechoslovakia, and I rode a 250 for the first time. The uphills were so steep that there were ropes so the spectators could get up them. I didn't know the course was that bad until I got to the first uphill--I was scared to death! The finish line was about a 50-foot drop-off. I closed my eyes and went off it. That was a real motocross track. [After that] when I practiced I would use the hardest, roughest track I could make. I'd be practicing with Tommy Croft and he'd say, 'How do you ride on stuff like this?' I'd lap him every few laps. I'd tell him this is what they do in Europe."
 Hard-riding nice guy John...  Hard-riding nice guy John DeSoto, the "Flyin' Hawaiian," led the second moto but crashed out, ending his night. |  No one expected the Europeans...  No one expected the Europeans to attend in the midst of the Grand Prix season, but Arne Lindfors, Hallman and Andersson all made the trip. |  Gary Jones' Yamaha YZ250 was...  Gary Jones' Yamaha YZ250 was the trickest thing in its day, and propelled him to the inaugural AMA National Motocross Championship. |
As a local racer, Tripes was a front-runner on everything he rode, from his 100cc Penton Berkshire to a succession of CZs. Larger than average, Marty came to be known as "The Big Kid on the CZ" as he quickly moved up through the classes while still in high school. By '71 he had a ride with Montesa, and had won the Mammoth Mountain Motocross. But there was a minimum age to race professional motocross, and Marty wouldn't turn 16 for another year.
Son of a Czechoslovakian bike...
Son of a Czechoslovakian bike nut, Marty Tripes was destined to be a motocross racer. He rode for almost every factory, and likely would have won the 1978 AMA Supercross Championship if not for a mechanical problem.
Meanwhile, the AMA put together its own Trans-AMA Series, which put the Inter-Am out of business after a one-year struggle. But as an investment in the sport, the Inter-Am had succeeded beyond Dye's wildest dreams. His motocross business, Husqvarna West, was growing exponentially, and at the end of '71 he went looking for a general manager. He hired legendary flat-track racer Everett Brashear, who was instrumental in founding the Husqvarna Motocross School at Carlsbad with World Champion Rolf Tibblin of Sweden.
Every dream starts with a crazy idea, and supercross was no exception. One day promoter Mike Goodwin called Everett to ask if he could talk to Tibblin about building a motocross track in the L.A. Coliseum. Everett told him he was crazy, but Tibblin was intrigued with the idea. "We can make it look good," he said. "It won't be a motocross track, but it will work."