From Culoz (804 ft / 245 m) to the Col du Grand Colombier (4,915 ft / 1,498 m) it’s 11 miles (17.7 km) at an average of 7.1% with 4,134 ft (1,260 m) of climbing. Along with the Chasseral, it’s the highest road pass in the Jura, and a much harder climb than its average suggests.
What the climb is like
- Km 0 to 1.5 (miles 0-0.9). You leave Culoz on gentle grades of 3 to 6%.
- Km 1.5 to 7 (miles 0.9-4.3). The first hard block: kilometers at 7.5, 9, 10 and even 12%, with odd ramps of 13%, through forest and bends above the Rhône valley.
- Km 7 to 9.5 (miles 4.3-5.9). A false flat at 1.5-5% where you can recover.
- Km 9.5 to 13 (miles 5.9-8.1). Past the Anglefort junction, it gets hard again: kilometers at 8.5-11%, with the odd ramp above 13%.
- Km 13 to the top (mile 8.1 on). A short flat breather and a final 1.9 miles (3 km) at 5-10%, with the last kilometer at 10%, out in open meadows with views of Lac du Bourget and the Alps.
A note on the numbers
CyclingCols gives 11 miles (17.7 km) and 4,137 ft (1,261 m); Climbfinder, 11 miles (17.7 km) and 4,134 ft (1,260 m), both at 7.1%. Wikipedia and cols-cyclisme measure 11.4 miles (18.3 km) and 4,117 ft (1,255 m) (6.9%), with a slightly different start. The steepest ramp ranges from 12.8% (Climbfinder, over 330 ft / 100 m) to 14.2% (CyclingCols).
History
The Tour de France first climbed it in 2012, on stage 10, with Thomas Voeckler leading over the top and winning in Bellegarde-sur-Valserine. In 2020 it was a stage finish, won by Tadej Pogačar on his way to his first Tour title; it returned as a finish in 2023. It’s also a regular in the Tour de l’Ain, the Dauphiné and the Tour de l’Avenir.
When to go, water and traffic
It closes in winter because of snow. There’s little traffic. Fill your bottles in Culoz: there are few services on the climb. You can descend via Anglefort or Artemare and make a loop with two sides.
What gearing to use
For the 12-14% ramps, fit a 34x30 or 34x32. At 3 W/kg and 159 lb (72 kg), you’ll ride about 5 mph (8 km/h) on 11%: 58 rpm in a 34x30 and 62 in a 34x32. Run your numbers in the gear calculator.
Frequently asked questions
How long does it take to climb the Grand Colombier from Culoz?
A 159 lb (72 kg) rider on a 21 lb (9.5 kg) bike takes about 1 h 27 min at 3 W/kg (216 W), 1 h 44 min at 2.5 W/kg and 1 h 07 min at 4 W/kg. Work out your own time with your weight and power in the calculator on this page.
What is the hardest side of the Grand Colombier?
The Artemare side via Virieu-le-Petit, to the west: 9.6-9.9 miles (15.4-15.9 km) at 7.8-8.1%, with sections over 20% according to Wikipedia. The Culoz side is longer but a little gentler.
When has the Tour de France finished on the Grand Colombier?
In 2020, won by Tadej Pogačar, and in 2023, when Michał Kwiatkowski was first to the top. The Tour first crossed it in 2012, with Thomas Voeckler leading.