Tour de France 2025 - 18th stage: Vif - Courchevel Col de la Loze | 171.5 kilometres | 5450 vertical metres
The 18th stage will be particularly tough for the riders who were at the front yesterday. The official road book indicates 5450 metres in altitude. Chamois qualities are therefore required, sprinters fight for survival alone or in a group.
We are likely to see two races again, the battle of strong climbers for the stage win and of course the fight for the podium in the overall standings. The Col du Glandon and Col de la Madeleine will provide the pre-stage fatigue, while the Col de la Loze will be the decider. After the Ventoux stage, breakaways will be even more motivated to seek their salvation in the escape. But it will also be even harder to accumulate enough time buffer against the GC riders, as it is all up and down and the effects of slipstreaming are less than on the flat approach to Mont Ventoux.
The Col de la Loze is not super steep throughout, but is still one of the toughest climbs on this tour due to its length and pre-tiredness. Apart from a very short intermediate descent, it is 26.4 kilometres uphill. The climbing time will be just over an hour, even for the fastest riders. The steep passage at the airfield, 5.4 kilometres before the finish, is predestined for an attack.
In our simulation, we take a look at which bike promises the fastest overall riding time on the final climb - under the premise of even climbing from bottom to top.
The number of the day: 1:02 minutes
A good minute lies between the fastest and the slowest bike in our calculation. The usual suspects are at the front, lightweight bikes with aero features. If there is a long attack in the classification, Jonas Vingegaard has a slight advantage over Tadej Pogačar. His bike is mathematically 19 seconds faster than the leader's.
The (almost) complete field at a glance*
The table shows the riding times for the Col da la Loze with the same riding style. Bikes that are light and aerodynamic have the tyre in 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.
Review of stage 16: Aerodynamics on the mountain
The Ventoux stage went as expected. On the approach to the Ventoux, the riders burnt a 50 km/h average onto the hot tarmac. The only surprise was that the group was so large. The wind that we had expected was actually blowing on the climb and a good bike aerodynamicist like Ben Healy knew how to utilise this and rode uphill so quickly to the interim leader Enric Mas because he climbed particularly aerodynamically. In the end, however, the Frenchman Valentin Paret Peintre had the faster legs than Healy. Top speed on the last 500 metres (which were steeply uphill): 30.3 km/h.
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.
