Sitting in the

Slipstream

The history of cycle racing and record

breaking shows us that cyclists have

understood about slipstreaming from

the very beginning.

AVING another rider in front of you

means that he is doing all the hard

work in pushing the air out of the

way and, if you tuck in close enough behind

him, you can cycle in a pocket of still air, his

slipstream, keeping up with him however fast

he goes, but putting in only a fraction of the

effort that he has to. Think of walking into that

blustery wind again. It’s much easier if you can

crouch down behind someone else, isn’t it?

H

Cyclists in road races like the Tour de France
see a reduction in air resistance of up to 35% if
they are close enough behind the man in front
of them. If they are riding in a closely bunched
group called a peloton (French for ‘little ball’),

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the cyclist in the heart of the pack might be

benefiting from as much as a 40%

reduction in drag.

They use the slipstreaming technique in motor

racing, too, where an even more interesting

effect emerged in the American NASCAR

series. At the Daytona 500 race in 1960, Junior

Johnson was struggling in practice when he

and his pit team realised that the other teams

were hitting top speeds over 20 mph faster than

his car could manage. Then Johnson noticed

that, if he tucked in close behind one of the

faster cars, he could keep up without even

using full throttle. The slipstream was helping

him to hammer round the circuit faster than he

thought was possible in his car. He then used

Below: Because Rider 1 is working hard to force the

air aside, he creates a pocket of lower-pressure air

behind him. Cycling in this pocket, Rider 2 can easily

keep up using far less energy.

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28    Britain’s Fastest Bike