The Galibier is the big one, and it knows it. At 2,642 metres this is one of the high gates of the French Alps, the saddle where the Maurienne valley to the north hands you over to the Guisane and the Briançonnais to the south, and the road crosses it by way of a short tunnel under the actual crest, or, for those who want the proper view, by the final few hundred metres of open hairpin that go over the top. The summit marker stands on the old crest, with a monument to Henri Desgrange, the founder of the Tour de France, who first sent the race over this pass in 1911. Cyclists still turn up in swarms to touch the sign, so expect lycra and an unhurried pace.
From the north you climb from Valloire, past the Col du Télégraphe, a gentle warm-up through forest, and then the landscape strips off its trees and turns to bare scree, rock and sky. From the south you rise out of the Guisane valley through Le Monêtier-les-Bains and the stunted larch above the village, then across the broad bowl below the Lautaret. The south side is the more open and fast, the north the more intimate, but both are well graded, wide enough for a big bike and rewarded with views toward the Meije and the glaciers of the Écrins when the cloud allows.
Do not treat it as an all-year road. The Galibier closes with the winter snow and typically only opens around early summer, then shuts again around October, so check before planning anything near the edges of the season. The weather can change in twenty minutes at this height, so put on a layer at the top even if you rode up in a T-shirt, and watch for wet patches in the shaded hairpins where snow lingers into July.
Valloire and Le Monêtier are small villages, so if the tank is anywhere near half, fill up in the valley before you start; the nearest bigger town to the north is Saint-Jean-de-Maurienne, with Briançon beyond the Lautaret on the other side. At the top there is usually a seasonal café or refreshment stand in the warm months, which does the job for a hot drink and a sandwich, but do not count on it being open early in the day.
Stay a few minutes. The air is thin, the colours are chalk, rust and green, and the marmots near the road whistle at you like annoyed neighbours.