From Arreau (2,287 ft / 697 m) to the Col d’Aspin (4,885 ft / 1,489 m) it is 7.5 miles (12 km) at an average of 6.6% with 2,598 ft (792 m) of climbing. It is the pass that links the Aure and Adour valleys, between the Tourmalet and the Peyresourde, and one of the Tour de France’s most traveled climbs.
What the climb is like
- Km 0 to 2. You leave Arreau on the D918 at gentle grades, 3 to 5.5%.
- Km 2 to 6. Past the turnoff to Aspin-Aure, the grade rises to 5-8% through Les Abos and Larrieu, with a few easier stretches.
- Km 6 to the top. First in the forest and then across pasture, the road never drops below 7%: kilometers at 7.5, 8.5, 9 and 8%, very steady, up to the pass. The last 3.4 miles (5.5 km) average 7.9% according to CyclingCols.
On the upper part it is common to meet loose livestock on the road.
A note on the numbers
CyclingCols gives 7.5 miles (12 km) and 2,598 ft (792 m) at 6.6%; Climbfinder 12 km and 2,621 ft (799 m) at 6.7%; and Wikipedia and cols-cyclisme 12 km and 2,556 ft (779 m) at 6.5%. The maximum grade is between 9.5 and 10%. There is another climb from Arreau via Aspin-Aure, shorter and a little harder (6.7 miles / 10.8 km at 7.3%).
History
The Aspin was first crossed in 1910, with Octave Lapize in front, on the stage that introduced the Pyrenees to the Tour. Wikipedia counts more than 70 Tour crossings, because it is the natural link in the Tourmalet-Aspin-Peyresourde chain. Riders who crested it first include Fausto Coppi (1951), Julian Alaphilippe (2018), Thibaut Pinot (2022) and Lenny Martinez (2025).
When to go, water and traffic
It can close in winter because of snow. Traffic is light outside summer. Fill your bottles in Arreau; there are no permanent services at the top. There are kilometer markers for cyclists showing the grade of the next kilometer.
What gearing to use
A 34x28 is enough for most riders: 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%, about 72 rpm. Below 2.5 W/kg, a 34x30 will let you keep a higher cadence. Check it in the gear calculator.
Frequently asked questions
How long does it take to climb the Col d'Aspin from Arreau?
A 159 lb (72 kg) rider on a 21 lb (9.5 kg) bike takes about 56 min at 3 W/kg (216 W), 1 hr 06 min at 2.5 W/kg and 43 min at 4 W/kg. Work out your own time with your weight and power in the calculator on this page.
Which side of the Col d'Aspin is harder?
The Arreau side. From Sainte-Marie-de-Campan it is 7.8 miles (12.6 km) at 5% and only the last 3.1 miles (5 km) are demanding; from Arreau, 7.5 miles (12 km) at 6.5-6.6% with almost the whole second half at 7-9%.
How many times has the Tour de France crossed the Aspin?
According to Wikipedia, more than 70 times since 1910, almost always linking the Tourmalet and the Peyresourde.