Could we see ‘le plank’ at this year’s Tour de France?
Friday 30 June 2017
Reading time: 3 minutes
It’s the latest unconventional riding position. Here’s why adopting it could make you quicker – without needing to pedal.
Last year we saw Chris Froome pedal to his third Tour de France victory. He grabbed an initial lead over his rivals while flying downhill in an unconventional tuck position.
The interest surrounding the move had many speculating on the advantages gained and even some computational analysis which concluded that the safer, standard descent style may have been quicker.
It wasn’t Froome’s risky descending which caught my imagination though. It was a video I spotted a while back which shows a much riskier (and arguably much more effective) descending technique.
In the video above we see a cyclist riding a fixed-wheel bike (one gear, no freewheel) before being passed by a group of cyclists pedalling standard, geared bicycles. With a fixed gear he isn’t able to pedal faster and so he adopts a crazy position — a solid, horizontal plank propped on top of the saddle. A number of things are clear from this point on.
• Despite the fact he’s stopped pedalling he begins to accelerate.
• Despite the fact the other cyclists are still pedalling, he passes them all.
• The lead cyclist, in a tucked position and pedalling furiously, is unable to accelerate to match his speed.
How could this plank pose be so effective?
I have constructed two simple models of a traditional cyclist and one in the plank pose, racing head-to-head downhill.
1. No pedalling test
Result: Clear victory for plank cyclist
As you can see, after a few seconds the superior aerodynamics of our prone cyclist begin to yield an advantage until his increased speed results in him disappearing from view.
However, we’d expect this wouldn’t we? Neither cyclist is pedalling and we know our planking cyclist is more aerodynamic. I think the real question is how much of an advantage does the improved aerodynamics give?
2. Elite racer vs ‘Superman’ pose
For my second animation I’ve given our normal cyclist an advantage — he’s elite level. This cyclist is able to generate a continuous output of 500 watts.
How does this head-to-head look?
Result: After two minutes, plank cyclist overtakes
The beginning of the race is not surprising. Our normal cyclist is able to generate a large amount of power to accelerate quickly while our plank cyclist only has gravity. At low speed aerodynamic forces are very low and the plank cyclist is left in the dust.
After some time our normal cyclist reaches a happy equilibrium. The propulsive forces are equal to his drag. What may come as a surprise is that after some time our unpowered, plank cyclist comes from behind to race past.
So, could we see this position at this year’s Tour de France?
Going back to our original question, I can’t see anything so extreme being attempted in the fastest race in the world.
But as my model shows, there are countless examples where paying attention to aerodynamics can give cyclists the crucial edge.