First TDF Mountain Stage

Stage 6

The first mountain stage of the Tour is upon us; the peloton will cross six categorized climbs totaling 35km leading up to La Planche de Belles Filles. In the Vosges region of France there aren’t the 2500m summit finishes like in the Alps or Pyrenees, but the Stage 6 summit finish will bring the difficulty in terms of gradient; the 7km climb has nearly 9% gradient and is actually steeper than that because of two flats near the finish. This is the fifth steepest of the categorized climbs in the race and at 7km it’s double the length of the four steeper climbs.

This means all that climbing will put serious hurt into the GC contenders, and then make them tackle a brutal finishing climb. The climb to La Planche de Belles Filles has been climbed three times recently; in 2012 there was little climbing ahead of time and a select group including Froome and Wiggins from Sky survived to the end; in 2014 – like Stage 6 this year – the peloton crossed six categorized climbs before the finish and Nibali rode away to gain slightly on his rivals; in 2017, there was little climbing beforehand and Fabio Aru beat a group of less than ten climbers.

For tomorrow, the market – such that it is – makes Bernal about 20% to take the stage win, with Pinot and Adam Yates as the next favorites. Dan Martin, Thomas, Valverde, Fuglsang, Landa, and Bardet are considered next likeliest to win.

Summit finishes

We see fewer breakaways stay away to win on summit finishes than mountain stages which end with a downhill or flat. In grand tours, 42% of mountain stages ending in downhills/flats see the winner gain 3 minutes or more on the eventual race GC winner vs just 20% of summit finishes. In the three stages all ending in summit finishes at La Planche de Belles Filles, the GC group has contained the stage winner every time. It’s unlikely a breakaway survives to the end tomorrow.

Climbing Performance

In the last post breaking down how grand tour winners gain their advantage, we found that about 50% of the gains in the last 19 grand tours came on climbing stages and 15 of those 19 winners have been the top climber in that race. This year’s TDF is one of the toughest climbing Tours ever with five true summit finishes and the largest total KOM climb difficulty of any grand tour since 2013. Already, the two favorites –  Bernal and Thomas – have created small time gaps on every other contender besides Steven Kruijswijk, so those trailing will need to ride aggressively to try to create time gaps.

In this post discussing measuring climbing performance, we proposed a method to evaluate climbing based on the time gaps compared to the 10th place finisher on a stage. We then adjust for the difficulty of the climbing on that stage (with the idea that tougher climbing stages give the opportunity for more time gains). You can measure that resulting Climb Gains metric over multiple years by taking either the median value or the average of the top 75 percentile values.

Entering this TDF, these are the top climbing performers based on median performance in mountain stages (considering long-term performance back to the 2016 TDF). I’ve ignored Froome, Dumoulin, and Miguel Angel Lopez who are missing this TDF; Lopez would rank just after Bernal, Froome after Martin, and Dumoulin after Valverde.

1. Egan Bernal
2. Dan Martin
3. Romain Bardet
4. Nairo Quintana
5. Rigoberto Uran
6. Mikel Landa
7. Alejandro Valverde
8. Adam Yates
9. Thibaut Pinot
10. Steven Kruijswijk

Thomas ranks 12th in the this year’s TDF and Fuglsang is 14th.

As a sense-check, Froome has entered the seven grand tours he’s raced since 2015 ranked 1st in long-term performance five times and 2nd twice. The leader in climbing during that grand tour has ranked 1st in long-term climbing performance five of thirteen times, with a low of 22nd and median of 3rd.

These ratings have been tested on stage level results and also on grand tour climbing performance. Below is a table showing the model probability for a rider who enters ranked N within climbers in that grand tour finishing as the #1 climber and one of the top 3 climbers.

Climbing Rank Entering Tour de France Probability of Ranking as #1 Climber Probability of Ranking as top 3 Climber
1st 28% 59%
2nd 15% 40%
3rd 10% 29%
5th 5% 16%
10th 2% 6%
20th <1% 2%
50th <1% <1%

The main blindspot for this model is factoring in short-term form for riders who have completely transformed themselves before the race. Eg, Geraint Thomas was not riding like a GC level contender until the Dauphine in 2018; he had ridden 9 straight mountain stages from March 2017 to April 2018 without a single GC level performance. However, he was 4/4 in the Dauphine and would have rated 22nd best in the climbing model going into the TDF.

This year, Fuglsang and Adam Yates are the favorites who have improved the most relative to their long-term performance. Including short-term performance in models improves the performance and comes out as a significant predictor, but it is much noisier and subject to the concerns floated at the end of this post.


For the better part of a decade, we’ve seen climbing stages in the TDF largely controlled by Team Sky who have super-domestiques like Wout Poels and Michal Kwiatkowski to consistently ride at a high tempo on the climbs. In this year’s Tour, I’ll be tracking how long Sky can keep support riders in the GC group, how tempo changes when the likes of Poels and Kwiatkowski drop away, and most importantly who can stick around through the relentless pace-making.

Yellow Jersey

Alaphilippe has some live probability of maintaining the yellow jersey past Stage 6. We’ve seen him win two stages of the Tour last year in the high mountains so there’s a least a chance he can stick with the GC group up to the high reaches of the the finishing climb. But he’s ridden 17 stages in his career with similar climbing difficulty as tomorrow (that also end with a summit finish); on only two occasions has he managed to stick with the GC group (in back to back days in the 2016 Dauphine).

With a strong climber like Steven Kruijswijk just 25 seconds back and Bernal/Thomas within a minute, the odds are long. It’s also possible Alaphilippe doesn’t even try to keep it; Stage 8 and 9 are both perfect for him to grab another win, and that’s much more likely if he conserves his energy and loses 5-10 minutes on Stage 6.

Working on the assumption Alaphilippe won’t finish with or near the GC group, Kruijswijk’s path is simple: stick with the GC group of Bernal/Thomas. Besides Bernal/Thomas who can get it simply if Kruijswijk can’t keep their pace, Michael Woods, Enric Mas, and Wilco Kelderman climb well enough, are close enough in the GC, and – crucially – are unlikely to be chased down by INEOS if they do try a move in the closing KMs (unlike Pinot or Uran).

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s