Tour de France 2025 - 15th stage: Muret - Carcassone | 169.3 kilometres | 2400 vertical metres
The 15th stage is unlikely to bring any changes in the classification. Breakaways will try to get through, the sprinter teams will hold out. Today is likely to be the penultimate opportunity for a sprint.
However, the sprinter teams will be very busy controlling the breakaways and manoeuvring their sprinters over the two mountains of the day. The second mountain of the day has a gradient of up to 9% - not terrain where the tough guys shine. Strong climbers will be faster here.
From the Col de Fontbruno, the last summit, there are still 42 kilometres to the finish. If a group at the front rides with gusto, it will be difficult for the teams to bring sprinters who have been left behind to the front. It depends on the quality of the breakaway group what the finale will look like. But a sprint from a group seems the most plausible scenario. The wheels of the day are set: Aero is everything!
This tour is ridden so hard - usually from kilometre zero - that it is absolutely clear what is important, namely to slip through the wind as well as possible. At 50 km/h, air resistance is absolutely dominant. And the longer a rider is exposed to the wind, the more important it becomes to save energy over the entire distance in order to have reserves in the finale.
In our simulation of the day, we don't let top sprinters compete against each other, but tired breakaway riders who open the sprint after a tactical skirmish from a slow pace 200 metres before the finish.
The finishing straight in Carcassone on Boulevard Marcou is slightly uphill, after a slight left turn it's a straight 200 metres to the finish. Which bike is most useful in these conditions? Does the weight have a greater impact when the initial speed and top speed are lower than in a bunch sprint with riders?
The number of the day: 14 hundredths
The Cervélo S5 wins the sprint with its combination of very good aerodynamics and low weight. However, the Van Rysel RCR-F Pro is very close despite being overweight, as is Mathieu van der Poel's Canyon Aeroad, which we weighed. This means that even in this slower sprint, aerodynamics neutralise excess weight. Once again, the light bike from Cervélo is the slowest, 14 hundredths behind.
From a technical point of view, all the details are important in a final like this: Bike, clothing and position. The sum of many technical details determines who comes out on top. Always assuming that the legs each deliver the same performance.
Disposing of the bottle before the finish sprint is also one of the little things. Not because of the weight, but because the bottle causes a few watts of additional aero resistance on the down tube.
The (almost) complete field at a glance*
In the 200 metre sprint at low speed, the lightweight and aerodynamic Cervélo S5 is once again at the front.
*) 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 not yet been able to analyse last-minute prototypes. Background to the simulation.
Our expert
Robert Kühnen studied mechanical engineering, writes about technical and training topics for TOUR and develops test methods. Robert has been refining the simulation calculations for years and they are also used by professional teams.
