Tour de France 2023 - Stage 5: Pau - Laruns | 162.7 kilometres
It's off into the mountains. A strong escape group could have a chance of getting through and riding for the stage win. But which bike does a rider who has set his sights on something choose? A light mountain bike? Or would he prefer a machine that is as aerodynamic as possible?
For the first part of the stage, the situation is clear: an aero bike would help to get away from the peloton and roll towards the first climb while conserving energy. But then the Col de Soudet rears up, 15.2 kilometres long and 7.2 per cent steep on average. The road surface is also rough. Further on, the even steeper Col de Marie Blanque has to be climbed (7.7 kilometres with an average gradient of 8.6 per cent), which even has a gradient of up to 13.6 per cent at the top.
Slightly uphill finishing straight on stage 5 of the 2023 Tour de France
And after all, escapees still have to be beaten. If the escape group were to sprint for victory at the end, the riders would have to deal with a slightly uphill finishing straight (10 metres over 1000 metres). All these factors need to be taken into account when choosing the right equipment.
Let's assume that the escape group climbs the Col de Soudet with an even effort after gaining a lead in the valley: Would an aero bike be a big disadvantage? No, if you don't ride at the limit, you could compensate for the extra weight. And if you had to ride at the limit to keep up with the group, you wouldn't stand a chance anyway. According to this calculation, the aero bike would therefore be useful up to the foot of the Col de Marie Blanque to save energy and keep the chasers at bay.
The most likely breaking point for an escape group would be the second half of the Marie Blanque, as it gets much steeper here. If you want to ride for the stage win, you have to be able to go on the attack here. We therefore simulate an attack 3.7 kilometres before the summit of the Marie Blanque. It takes around 15 minutes to reach the summit.
Number of the day: 9 seconds
The light bike has an advantage over the heavier aero bikes in an attack at the key section of the Marie Blanque. The lightest bikes in our list are at the front in this scenario: Giant and Wilier.
The probability of being able to follow the decisive attack therefore increases if the rider is on the lightest possible bike. If you think the scenario we've outlined here is likely, a lightweight mountain bike is therefore the bike of choice.
To take the edge off the rough Pyrenean roads and optimise grip and rolling resistance, tyres that are not too narrow are a good choice. Riders with a sense for rubber fine-tuning could go from 28 to 30 mm wide tubeless tyres to roll over these roads in the best possible way.
The (almost) entire field at a glance
*) 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.
