8/2/07

Slow Bikes – A Tour de France Special on Slipstreaming

Every July, skinny men on colourful bicycles pedal up mountains in the Tour de France. The riders average over a hundred miles per day for three weeks. How do they do it? Fitness and technology are only part of the story; no rider could be competitive without the invisible boost of the slipstream – the same effect used in NASCAR and by dicing GP racers like Gibernau and Rossi.

At 25mph, roughly 90% of a cyclist’s effort goes into moving air out of his way. Slipstreaming cuts that figure dramatically. In a pack, all but the front row of riders feel the benefit of the draft (there's very slightly more to it than that, and it involves vacuum--the first riders get a tiny benefit from the people behind them), so they take turns slipstreaming to conserve energy. This energy-saving teamwork is the reason a group of riders can catch a solo breakaway with relative ease.

Want to feel the spooky calm of the draft? Get hold of a racing bike and find a bus route along a 30mph street – you’re going to draft a bus. Ride along the route until you pass a stationary bus, then shift into a big gear and accelerate hard as the bus pulls away. Once it passes you, check there are no cars and then duck in behind it, maintaining a distance of 5-10 feet. You should hardly have to pedal, and the wind will disappear. Cover the brakes in case the bus begins to slow.

It is much easier to ride a hundred miles a day if you barely have to pedal. Indeed, a pro rider generates less than 1bhp. So if you cannot arrange the suggested thrills, fear not. Hop on a Fireblade and you’ll be sitting on more power than is in the entire Tour de France peloton.


6 comments:

jmg said...

I just discovered your updated blog! (I must have linked to an old version.) I am looking forward to reading it.

Joanna Goddard said...

that's a great illustration at the top.

SW said...

Tempted to try drafting with the bus but I would be the jerk who runs into the bus!

Anonymous said...

The F1's acceleration is phenomenal - ooch.

Nick Goddard said...

So, that's not an F1 car, its a Suzuki Hayabusa (not a fireblade, sorry I couldn't find a video). You can buy one secondhand for about 6k USD. ROW!

lopi said...

I knew a guy who turned a Hayabusa into a dragster bike. What a waste! All the fun in bikes is in the way they turn, not their acceleration. IMHO, always.