Tour de France 2025 - Stage 7: Saint Malo - Mur de Bretagne/Guerlédan | 197 kilometres | 2450 vertical metres
The finale of the seventh stage promises great cinema. Mathieu van der Poel triumphed here for the first time in 2021, winning the stage in superior style.
We can assume that he has the final on his agenda again. Tadej Pogačar will also want to be in the mix again and Jonas Vingegaard, who has already shown sprinting qualities uphill several times in this Tour, can also be expected at the front. A remake of the finale of the fourth stage is conceivable.
The Mur de Bretagne is a climb of only 140 metres in altitude, up to 15% steep at the top, which is ridden twice in the finale and also represents the finish. If you want to win here, you need agility and stamina. The latter especially when the attack comes on the first crossing.
This is exactly what we simulate: Starting at the first passage and extending to the finish. What influence does the bike have on such a finale? Which machine has the front tyre?
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The number of the day: 36 seconds
36 seconds are lost by a rider who attacks on the slowest bike in the outlined finale. In our calculation, this is the Cervélo R5. It is possible that the new R5, which has been overhauled, has become slightly more aerodynamic than its predecessor, whose values we expect. However, in view of the subtle changes, we don't expect a radical improvement. Our weighings show that the R5 can keep within the 6.8-kilo limit, so it is light. However, the detailed analysis shows: The R5 even has disadvantages in the sprint on the ramp compared to the equally light but much sleeker S5, which also wins the over-all evaluation of the simulation with a two-second lead over the Van Rysel RCR-F Pro, which is a little too heavy for a steep ramp.
This puts two aero bikes in the lead, followed by other bikes of this type. Aerodynamics determine the ranking.
The (almost) complete field on the final lap*
The table shows that aero bikes are the first choice in an early attack to save the lead to the finish.
*) 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.
Review: Crazy speed, aerodynamics increasingly important
Looking back at the stages so far, we can see that aero bikes and aero features are playing an increasingly important role in the Tour de France. The riders are very dynamic, the pace is horrendous and even on rather inconspicuous stages, gaps in the overall classification are being pulled out.
Tadej Pogačar has made friends with his Colnago Y1Rs, which has only been used sporadically in the run-up to the Tour de France, but is a big improvement on his Tour bike from last year. Up to this point, the Y1Rs has been Pogačar's machine of choice for this Tour.
We had outlined that the slightly lighter V5Rs would have been a small advantage in an attack on the 15% ramp on the fourth stage. Pogačar launched his expected attack on the steep section, but rode the Y1Rs, not the V5Rs, which we thought would be faster in this situation. He pulled the pace up to 24 km/h on the 15 per cent and initially distanced Jonas Vingegaard until the latter came to his senses and caught up with the second air - on his sleek and light S5.
However, the challenge for the two leaders was to keep the following pack at bay. Despite the teamwork of the two superstars, both on very fast bikes on the descent and therefore optimally equipped, the pursuers caught up again on the downhill in a situation where aerodynamics were the deciding factor. The light bike would have cut a worse figure in this passage.
It came down to a sprint on the less steep final climb, in which Pogačar was able to beat Mathieu van der Poel by two bike lengths. Followed by Jonas Vingegaard.
What a final! The best riders in an open exchange of blows - on largely mature material, which therefore had no influence on the sporting decision.
Facts about the Colnago Y1Rs
We were able to test the Colnago Y1Rs in the wind tunnel in the run-up to the Tour de France. Aerodynamically, it is much better than last year's V4Rs and catches up with the fastest bikes in the field.
The graph shows the aero performance of the Colnago bikes from last year and this year at different wind attack angles, as caused by crosswinds - measured in the GST wind tunnel according to the TOUR protocol with moving legs.
The improvement of 15-20 W at a speed of 45 km/h over the entire approach flow range is massive! Last year, Tadej Pogačar was riding with a handicap, but now his equipment is on a par with the best bikes.
The influence of the wheels and tyres on the aero performance can be seen from the curves. We weren't able to test the bike with the Enve 4.5 wheels that Pogačar rides on the Tour. These are presumably faster than the Vision wheels in the production bike that we had in the wind tunnel (weighted 204 W resistance). As a test, we put the fast DT Swiss ARC 1100 50 with the Aero 111 front tyre into the Colnago. With this tyre, the bike sails and performs better, especially in crosswinds. The weighted resistance even drops below the magical 200 W limit to 199 W.
However, Tadej Pogačar rides so fast that he rarely experiences an angle of attack of over ten degrees. An aero tyre would primarily give him handling advantages at high speeds: the front wheel fidgets less in gusty winds. This year, however, Pogačar is not riding the aero tyres but a new development from Conti with a focus on less rolling resistance. We will discuss this in one of the next briefings.
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.
