The Physics of Motocross - Smarter Every Day 30

Hey, it's me Destin. I have been invited out to a professional motocross racer, Ryan Sipes, at his house, and today we're going to talk about how to control a motorcycle.

Alright, so we're in rural Kentucky, and we've got the V10 high-speed camera again and a bunch of jumps. Let's say that you go over on the bike and you're coming up too high, and you need to rock it back down. So, all you do is, if you've got a flywheel going here, you've got rotational energy stored up here: 1/2 I Omega squared.

And so what you do there is you just tap your brakes. You can, like, tap your brakes, and once you do that, that transfers this rotational energy to the whole body of the bike. And once you do that, then you'll rock it back over. Ryan's going to demonstrate that for us because he does that intuitively.

Ok, ok, I'm filming. Explain that again; I didn't get it.

So basically, what you want to do—what I mean by the technical term behind it—is you're going to want to keep the vertical inertia of your sprocket bearings, right? Okay, and your front swing arm caliper vertex equal to X.

Rick, oh wait, what? No, that's like... I mean, we all had to learn it, alright? So college boys get made fun of here. You...