The Science of Cycling | StarTalk

There's drafting-- something we know about in NASCAR and other very fast races. But there's also drafting in cycling. It's crucial in cycling. In Tour de France-- so somebody in front of you, you can get an advantage from that. You certainly can. The energy that you need to expend reduces up by maybe 30%. So I asked Lance about that. Let's see what he says about drafting.

So let's talk about drafting. OK. It's one of the most important parts of the sport. So presumably there's some speed below which drafting is not useful.

Right. That would be like one mile an hour. No-- anything more than-- anything more than stationary. Keep in mind that the speed is important to talk about. But the wind is-- if you say 10 miles an hour, that's not very fast. But if the wind is 50 miles an hour in your face, 10 miles an hour is pretty fast.

So your draft-- it's just-- it goes up exponentially. The more intense the wind is, the direction of the wind, right? Obviously, if it's right in front of you, you stay right behind the rider that's in front of you. If the wind is from the left, then you inch over to the right.

Oh, OK. OK. So you just find-- this is why I say NASCAR. You find that sweet spot of where that draft is. And then, of course, that just gets multiplied. If there's one rider in front of you, you have a draft. If there are 100 riders in front of you, you're not even pedaling.

So Max, first, this sounds like-- it sounds lazy, first of all.

Oh, yeah. Yeah, yeah. And diabolical, because you're exploiting the energy of the leader. So then why does anyone lead the race?

Because that's their job. Because their team leader may be behind them. So they may be a domestique, one of these servants, to go out the front, to take the brunt of the wind so the people behind, their team leader, can save their energy by slipstreaming.

Now, what if the servant wins? [laughter]

That's good. That doesn't happen, Scott. That doesn't happen.

• Come on.

No, no, no. No one's ever gone rogue?

People go rogue on one day. But the next day, suddenly, they find they don't get out of the caravan. [laughter]