- Ascent
- 1911 hm
- Distance Ascent
- 38.6 km
- max. gradient
- 9 %
- ø gradient
- 5 %
The Col de la Bonette from Isola is an HC climb of 38.6 km with 1,911 m of elevation gain at an average of 5 %, peaking at 9 %. The road follows the Tinée valley via Saint-Étienne-de-Tinée up to 2,802 m, the third-highest finishing point in our list of 100 climbs. On the far side it drops into the Ubaye valley to Jausiers.
The Col de la Bonette is a climb where length plays the lead role. From Isola in the Tinée valley it is 38.6 kilometres and 1,911 metres of climbing up to 2,802 metres. In our list of 100 legendary climbs that is the third-highest finishing point, only the roads to the Pico del Veleta and the Ötztal Glacier Road end higher. The Bonette never gets steep, it is simply very long.
The Col de la Bonette at a glance
The key figures from Isola: category HC, 38.6 km, 1,911 m of climbing, 5 % on average and 9 % at its steepest. The climb follows the Tinée upstream via Saint-Étienne-de-Tinée and tops out at 2,802 m. On the far side the road drops into the Ubaye valley to Jausiers. In our list the Bonette sits in the Maritime Alps region.
The climb from Isola
The kilometre profile splits the Bonette into two very different parts. The first 14 kilometres or so up the Tinée valley average less than 2 %, and some kilometres are practically flat. That is more approach than climb, and it is exactly where you decide how much strength is left for the top. From around kilometre 15 the road starts to rise in earnest.
From there to the summit the gradient mostly sits between 4 and 8 %, with no long flat sections in between. Taken on its own, this second part averages a little over 6 %, clearly more than the 5 % in the fact box, which the flat valley pulls down. The hardest kilometres come in the final third. Anyone who held back in the valley can ride this part at their own rhythm.
How it compares to our 100 climbs
At 38.6 km the Bonette is the fourth-longest climb in the list, only the Colle del Nivolet, the Pico del Veleta and the Col de l’Iséran are longer. For elevation gain it ranks sixth with 1,911 m, for the height of its finishing point third. On average gradient it lands in the bottom tenth at 5 %, and only two climbs in the list have a lower maximum gradient than its 9 %. Among the five climbs in the Maritime Alps it is the longest, the highest and the one with the most climbing, ahead of the Col de la Cayolle, the Col d’Allos, the Col de Turini and the Col de Tende.
Practical tips
The Bonette rewards patience: ride the flat first 14 kilometres calmly and there is enough in reserve for the second half at over 6 % on average. With a maximum of 9 % you do not need an extremely low gear, what counts is duration. At 2,802 m it is noticeably colder than down in Isola even in summer, so a windproof layer for the summit and the descent belongs in the jersey pocket. The descent to Jausiers in the Ubaye valley is the alternative to riding back down the Tinée valley.
