It doesn't get any flatter: on the way to Saint-Amand-Montrond, there are only 950 metres of elevation to climb on the 10th stage - there are also molehills over 187 kilometres. On paper, it is a stage in which Mark Cavendish could add another victory to his 35, especially as he already won here on July 12, 2013. The finishing straight is 500 m short, with four bends to negotiate between the Devil's Lap and the 500-metre mark. Clever positioning is therefore even more important than usual, which suits Cavendish's riding style.
If there is a strong wind, it could have a say in the open plains and cause the field to break up into echelons. If a strong wind blows from the side, the riders experience what our wind tunnel dummy experiences every day: the wind does not hit the riders head-on, but more or less diagonally from the side. The riders then stagger diagonally across the road. With this staggered riding style, the slipstream can be maximised in an oblique flow. Only the rider on the far edge of the echelon is working hard. Anyone who has no more room in the echelon is just as exposed as the leader of the echelon. However, the difference is that there is no rotation of riders in the tail of the echelon.
This is why the field usually breaks up. Riders who are left behind form new echelons. As a result, the field breaks up into small groups. Teams that are on their toes and have a good weatherman who can accurately predict the wind direction sometimes provoke this effect, quickly forming an echelon when changing direction and surprising their rivals.
The main effect comes from a clever riding style, but you can also use technology to help: Aero bikes and aero wheels provide the greatest advantages in strong winds. Sail-friendly front wheels can even be driven by the wind. An optimally equipped team can make all the difference. If head, legs and material work together optimally, a lot of time can be made even on an unimpressive course.
Tempo ride on the echelon: A 10-second lead over five kilometres is possible through bike technology alone - if we compare the aerodynamic with the less aerodynamic bikes. In reality, the achievable gaps are greater because motivation and riding technique have a greater effect than bike technique.
*) The calculations are based on the bikes tested by TOUR in the laboratory and wind tunnel. The bikes at the Tour de France may differ in some details. Of course, we have also not yet been able to examine last-minute prototypes. Background to the simulation.
The table shows the riding times over five kilometres when a team attacks hard. Aero bikes pull out a lead.
Just like on the windward edge, tactical overview was also required on Sunday's gravel stage. The top riders also experienced how quickly a gap can develop. One bad position and Primoz Roglic was suddenly over 30 seconds behind on the second gravel section. In the end, however, the top teams defused all the crisis situations, Roglic's gap as well as Jonas Vingegaard's flat tyre, who finished on the bike of his teammate Jan Tratnik. Visma | Lease a Bike showed a remarkably good team performance, rode confidently from the front and had obviously put on thicker tyres than usual. Tadej Pogacar attacked as expected. Ultimately, however, the course proved to be too easy to just ride away from everyone, especially as Vingegaard acted purely defensively and showed no interest in getting away from his team. As a result, nothing happened in the overall classification.
We would also like to take a brief look back at the first time trial. Remco Evenepoel's winning time beat our fastest simulation time by two seconds. This is a strong indication of how crazy good Remco Evenepoel's aerodynamics are. We had calculated with an average of just under 400 watts, a performance that Evenepoel had already achieved two years ago in a time trial at the Tour of the Algarve and (very briefly) documented on Strava before the entry was deleted again. An aero power of 205 watts for a speed of 45 km/h seems absolutely realistic, which corresponds to a cdA value of 0.175 m^2 - a dream value and the key to top performance.
That aerodynamics are the key to his success can also be deduced from the fact that he cannot keep up with the very best on the climbs, despite his relatively low weight. His physique seems ideal for time trials. His upper body lies behind the massive aero helmet, which together with his arms directs the airflow around his body. But the other top riders also looked very, very fast. Roglic saved the time trial with a very fast second half, which also speaks for good aerodynamics and downhill technique - both important factors with regard to the final time trial to Nice.
Robert Kühnen studied mechanical engineering, writes for TOUR about technology and training topics and develops testing methods. Robert has been refining the simulation calculations for years, they are also used by professional teams.