AeroCoach’s Dr Xavier Disley forecasts who will win the time trial on the final day of the 2024 Tour de France
After three weeks of hard racing, the 2024 Tour de France reaches its grand finale tomorrow.
In place of a ceremonial stage to Paris (this year’s Tour finishes in Nice because the Paris Olympics is about to take over the French capital), the race organisers have planned a final test contre-la-montre for riders hoping to take home the coveted yellow jersey or a stage win.
Mirroring the iconic 1989 Tour (when Greg LeMond stunned the cycling world by stealing the yellow jersey from Laurent Fignon by eight seconds on the final day), stage 21 is an individual time trial.
The race starts in Monaco, and will be familiar to many of the peloton – including Tadej Pogačar, who is accustomed to the second climb in Eze, having used it in the past for 5-minute hill repeats.
33.7km in length, the course profile follows a common theme in recent Grand Tour time trials, with a large central climb.
Here, there is a slight difference because the main climb is split into two, and although the elevation gained is nearly 700m, it will still be largely an aerodynamic test for the GC riders, rather than a pure hill-climb effort.
La Turbie
There’s just 2.7km of opening roads around Monte Carlo before the main climb starts in earnest at La Turbie – an 8.2km gradient at 5.7 per cent.
This climb will take more than 20 minutes for most in the race, but the top general classification riders (who can climb at more than 6 watts-per-kilogram) will be dipping under 19 minutes for this section.
A time check at the top of the climb will give a good indicator as to who is climbing well and who might be losing time.
Because the Tour de France is the sport’s most important race, there’s always a battle for every place in the GC and riders will be putting everything into their effort here.
On La Turbie, a difference of 1kg is worth 4.2W, or around 10 seconds.
A 10-watt improvement in power output will see a rider gain 24 seconds, though, which is most relevant for riders in the GC top 10, where the time gaps are still extremely tight in some places.
Given its length and gradient, aerodynamics will play a minimal role on the first climb. The average speeds for the top riders are unlikely to be more than 28kph, so we can expect to see them sat up with their hands on the base bars of their time trial bikes for most of the climb.
Starting with a road bike will be a mistake, though, because riders will lose too much time on the initial 2.7km to make up for the difference on the climb.
Looking at the weather forecast, the riders can expect temperatures in the mid-20s (ºC) with potentially some rain.
Given this, overheating won’t be as much of a problem as it would be with time-trial helmets in higher temperatures. We may see some riders placing their magnetically attached visors on top of their helmets, if this is an option, to increase convective cooling, though.
Riders will need their visors for the remainder of the race, so can’t get rid of them.
The UCI regulations also don’t allow for the removal of a helmet while riding, so riders can’t have a helmet swap on the bike at the top unless they stop riding, which wouldn’t be worth the lost seconds.
Given how riders have been climbing so far, we can expect to see the main GC protagonists at the top of the leaderboard for this first time check at the top of La Turgie.
Unless he’s on a bad day, Pogačar will be unlikely to lose time to rivals at this point, but Jonas Vingegaard will be giving it everything to make up the most time in case of a mishap or miscalculation from his great rival.
The reigning time trial world champion, Remco Evenepoel, may take back a few seconds in the flatter, opening 2.7km. Given what we’ve seen so far at this year’s Tour, though, he’s unlikely to be too close to Pogačar by the top of the climb.
Col d’Eze
Past the top of the La Turgie climb, there’s a small intermediate section before the climb out of Eze, which is 1.6km at 8.8 per cent.
This takes in a fast, non-technical downhill section where riders will be partially recovering from their ~20-minute effort up La Turgie, but the short climb out of Eze (which will take the riders around 5 minutes) won’t create as much of a time gap as La Turgie.
Riders who are spent from their opening effort could lose out, however – a 10-watt reduction in power output up Col D’Eze will result in a 7-second time loss.
We then have the second time check. Barring any major disaster, the GC leaderboard should look broadly similar to the first check, though.
In Grand Tour time trials, the non-GC riders hunting for a stage win will often go hard to the first time check and take stock of their position. If they’re off the pace, they’ll simply cruise to the finish, so we may see some familiar time trial faces give it a go to the first time check, but not feature at the second.
Descent to Nice
Next comes the descent, where (apart from a small 800m 3.7 per cent ‘bump’) it will be fast from 17km to 28km. This 11km stretch is technical and will require good bike-handling skills.
Averaging a turn once every 500m, there are four hairpins, in which riders will have to scrub off a lot of speed.
This is still one for the time-trial bikes, though – especially so with the long, 5km+ run-in to the finish line, where anyone using a road bike would be at a big disadvantage.
These days, all of the teams will have done enough analysis to understand the impact of running road bikes in time trials, compared with years past.
If we do see riders on road bikes, it will simply be because it’s their comfort or handling preference to just get safely through the final Tour stage – rather than targeting a performance advantage.
Gaining time on the descent will be mostly about bike handling and less about raw power. Given the risk of crashing, riders who have consolidated their GC position may well back off slightly to not risk any mishaps.
The final time check, with around 5km to go, will reveal who has taken it easier on the descent, and then it’s a straightforward run-in to the finish.
Pogačar could go for the stage win, but would have to take risks on the descent – we saw Vingegaard do this when in the race lead at last year’s Tour, though, so it’s not unheard of.
The final stretch is long enough to gain a few seconds back – an additional 10 watts is worth around 3 seconds in this final section.
What can riders do to improve their performance on this stage?
The top riders will be racing for less than 45 minutes, as long as the conditions are acceptable (too much rain on the descent will slow things down significantly), meaning nutrition and hydration aren’t as much of a factor as on other stages.
Equipment-wise, it will be nigh-on impossible to lose 1kg from a time-trial bike without adversely affecting the aerodynamics of the whole system, so more focus should be on the rider.
Are they going to overheat on the climb? Is there anything they can do with their clothing to mitigate it? A short-sleeve skinsuit or detachable visor, for example.
Pacing will also be key, given there’s more than 16km from the second time check to the finish line. With the current time gaps between the top three, though, something very dramatic would need to happen to upset the apple cart in the fight for the yellow jersey.
We may see riders choosing lighter equipment, such as a shallower front wheel, but this isn’t necessary because the weight savings aren’t enough to make it worthwhile.
Using a 2x or 1x drivetrain will also be something to consider given the course profile. A 2x drivetrain naturally has more range, but a 1x drivetrain can be more aerodynamic due to the absence of a front derailleur.
Whichever they opt for, we’re likely to see many riders using oversized chainrings for improved drivetrain efficiency.
Riders using 1x could climb in a 58x30t chainring/sprocket combination at 90rpm, giving them a speed of around 22kph – at the lower end of the speeds expected of the top riders.
Going to a larger, 60x30t combination is around 1kph difference at 90rpm while climbing, so that will also be an option for the strongest riders.
Overall, this time trial is certainly a good test for the general classification riders.
Riders can’t afford to be poor at handling their time-trial bike on the technical descent, 25 per cent of the race is pan-flat, and there’s a solid climb that needs to be tackled with precise pacing.
Whoever wins the stage will have proven themselves to be a complete rider against the clock.