From Jausiers (3,990 ft / 1,216 m) to the highest point of the loop around the Cime de la Bonette (9,193 ft / 2,802 m) it is 14.4 miles (23.2 km) at an average of 6.8% with 5,203 ft (1,586 m) of climbing. It is a long, steady climb with no brutal ramps, but it finishes at an altitude where the thin air weighs on your legs.
What the climb is like
- Km 0 to 5 (first 3.1 miles). You leave the Ubaye valley at gentle grades of 3 to 6%, which gradually increase.
- Km 5 to 15 (miles 3-9). The steadiest section: kilometer after kilometer between 7 and 9%, through the Grosse Combe ravine and Riou Versant, with the odd short break.
- Km 15 to 20 (miles 9-12). You pass the Lac des Eissaupres and the old Restefond barracks. The grade stays at 6-9% and the landscape turns to bare rock.
- The finish. You reach the Col de la Bonette (8,907 ft / 2,715 m) and, if you want the top elevation, carry on around the loop that circles the summit: a little over 0.6 miles (1 km) with 9-11% ramps up to 9,193 ft (2,802 m).
A note on the numbers
CyclingCols gives 14.4 miles (23.2 km) and 5,203 ft (1,586 m); Climbfinder 14.5 miles (23.3 km) and 5,207 ft (1,587 m), both at 6.8%. Cols-cyclisme measures 14.9 miles (24 km) at 6.6%. The maximum grade is around 10-11% on the final loop.
History
Wikipedia lists it as the highest point the Tour de France has ever reached. The Tour has come this way only a few times: Federico Bahamontes crested it first in 1962 and 1964, Robert Millar in 1993 and Richard Carapaz in 2024. The Giro d’Italia climbed it as well in 2016, with Mikel Nieve in front.
When to go, water and traffic
The road is only open in summer and can close for snow even early in the season. It is cold at the top and the weather changes fast: bring a jacket and gloves for the descent. Traffic is light, mostly motorcycles. Fill your bottles in Jausiers; after that there are hardly any services, just the odd mountain hut in season.
What gearing to use
The grade is steady, so a 34x28 or 34x30 is enough for almost everyone. At 3 W/kg (watts per kilogram of body weight) and 159 lb (72 kg), you ride about 6.8 mph (11 km/h) on 8%: on a 34x28 that is about 72 rpm. Above 8,200 ft (2,500 m) you will lose power, so a bigger cog will not go to waste. Check it in the gear calculator.
Frequently asked questions
How long does it take to climb the Bonette from Jausiers?
A 159 lb (72 kg) rider on a 21 lb (9.5 kg) bike takes about 1 hr 50 min at 3 W/kg (216 W), 2 hr 11 min at 2.5 W/kg and 1 hr 25 min at 4 W/kg. At this altitude you will put out a little less power than usual, so allow a few extra minutes.
Is the Bonette the highest road in Europe?
No. The Cime de la Bonette loop reaches 9,193 ft (2,802 m) and is the highest paved road the Tour has used, but the Col de l'Iseran (9,068 ft / 2,764 m) is the highest paved pass in the Alps, and there are higher dead-end roads, such as the one up Pico Veleta.
When is the Bonette open?
Only in summer. The road closes with the first fall snow and does not reopen until it is cleared in late spring; check its status before you go.