If it weren’t for a later spot of impromptu fell running, the descent of the Peyresourde would surely have provided the most memorable images of Chris Froome during this year’s Tour de France. Chest on the bars and pedalling while sitting on the top tube, the Team Sky rider used his distinctive descending position to win stage eight.
But is that position really more aerodynamic? Bert Blocken from Eindhoven University of Technology says not.
Blocken and his team have previously carried out research into the influence of race vehicles on riders’ speeds and they have now turned their attention to Froome’s Peyresourde efforts.
Scanning was performed to provide the geometry of a cyclist in four different positions: the “Froome position”; a more conventional descending position with the cyclist on the saddle, which they called “safer descent position”; a time trial bike position; and upright with hands on top of the bars. Numerical simulations were then carried out.
Writing on LinkedIn, Blocken concludes: “The “Froome position” – as opposed to common perception – is not more aerodynamic than a more common and safer position with the cyclist sitting on the saddle and bent forward with the head close to the handlebar. The distance between cyclist body and bicycle frame and between cyclist body and the ground is not a factor of importance in terms of aerodynamics.”
Blocken believes Froome took most of the time he gained during that descent by accelerating over the summit and because the chasing riders perhaps then adopted positions inferior to the “safer descent position” used in the modelling.
GCN also carried out a top tube experiment in the wake of Froome’s win. They measured the speed attained while descending in three different ways: pedalling on the top tube, not pedalling while on the top tube and pedalling in the saddle.
They found that the ‘full Froome’ pedalling on the top tube position was actually a second slower than pedalling in the saddle.
It should perhaps be noted that during this test, Dan Lloyd managed the perhaps unique feat of looking even more awkward on the bike than Chris Froome while pedalling on the top tube. It was also a fairly shallow descent, meaning lower speeds and therefore less wind resistance.