BMX Science: The Physics Behind a 360 One-handed Tabletop
Fly in the air on a BMX bike, spin a full 360-degree rotation and then land in perfect continuum ready for your next trick. Oh, and do it all with only one hand on the handlebars. That’s the focus of the BMX trick Mike “Hucker” Clark pulls off on a daily basis.
Brandon Larson, the Red Bull High Performance technologist, explains to Edge just how Hucker pulls off his aerial movements.
From the very start, Hucker needs the kinetic energy he has built up from the speed of the previous jump. To harness that energy properly, the video shows Hucker crouching slightly before heading up the ramp, an effort to gain more height or more angular momentum when he pops off the lip of the ramp.
“By crouching, he is adding potential energy to the system and when he pops, he boosts his kinetic energy off the take off,” Larson says.
Hucker adds extra torque on the take off by throwing his hips sideways, heading up the ramp slightly off center, and digging his bike into the ground with a front bar twist. This all serves to set his angular momentum—which won’t change, let’s call this the “law of conversation of momentum,” unless some outside force comes into play, a rare occurrence in BMX, unlike Moto X.
“By now, Hucker has carefully created the right amount of angular momentum on take off to have enough potential to spin to land his trick,” Larson says.
In the air, Hucker tosses his arm not just to look cool, but to adjust his rate of rotation, the moment of inertia. In general, moving his arm further from his body’s rotation slows down the rate of rotation and pulling his arm (his mass) toward the axis speeds up the rate.
In this video, Hucker pulls his body into his bike, increasing the rate of rotation and then throws his arm up to slow him down and make up for the increase in bike movement. Of course, as Larson points out, much-needed style points dictate some of the flourish.
During the mid-air movement, Hucker slowly brings his arm back down while moving his body away from the bike, cancelling out the rate of rotation changes in an effort to pull off a “controlled motion” and a smooth landing.
Tim Newcomb covers stadium, design and gear for Sports Illustrated. Follow him on Twitter at @tdnewcomb.