Newswise — Travis Pastrana's double backflip won the prize for best freestyle motocross (FMX) trick at the 2006 X Games. A new physics calculation shows that it's possible to do even more rotations, but a quad backflip is the best anyone will ever do with modern competition FMX bikes.
"I watched Travis win the FMX best trick competition at the X Games last year," says James Riordon of the American Physical Society in College Park, MD. "It was awe inspiring. But it made me wonder just how far this sort of thing can go. So I sat down to do some basic calculations to determine the maximum number of flips possible in FMX. The answer is a little more than three and a half rotations, which is the same as a quad backflip."
To do the calculation, Riordon started with the current record for the FMX equivalent of high jumping, which is known in the sport as the "step up" competition. The height determines the maximum amount of energy that a rider has at their disposal. Currently, the record stands at just about 11 meters.
To maximize flips, Riordon explains, about half the available energy must go into rotations and half has to go into getting altitude. "If you go too high, you'll spin too slowly, and if you spin too fast you won't go high enough to get enough hang time to make it around," says Riordon.
If everything goes perfectly, some future heir to FMX king Travis Pastrana will launch nearly straight up off a ramp, and perform a quadflip while flying about five and a half meters in the air.
Don't expect to see it this year though. The best anyone has done so far is a double backflip. A triple will be scary, but is well within the realm of possibility in the near future. When you've seen the quad backflip, you'll know FMX has pushed the trick to the limit.
To see details of Riordon's calculations, visit the American Physical Society website Physics Buzz (http://physicsbuzz.physicscentral.com/2007/07/quadflip-fmx-limit.html).