Cycling in the French Alps

The Route des Grandes Alpes is the classic road-cycling traverse of the French Alps, a 700-kilometre line from Lake Geneva at Thonon down to the Mediterranean.

It links the greatest mountain passes in the range one after another — the Cormet de Roselend, the Col de l'Iseran (at 2,770 metres the highest paved through-pass in the Alps), the Galibier, the Izoard, the Bonette.

It is a rider's pilgrimage, climbing many of the cols made legendary by the Tour de France, and the arc of the journey is the thing: from alpine lakes and high glaciated passes in the north to the sun-baked Provençal scent and the first sight of the sea in the south.

Over a week or so of long, hard days you cross the whole range under your own power, descending at last to palm trees and the coast. For a road cyclist who loves to climb, it is one of the finest routes on earth.

A week or more of hard road cycling, linking sixteen or more high alpine passes across roughly 700 kilometres and tens of thousands of metres of climbing.

Days follow a rhythm of long, sustained ascents to cols above 2,000 metres — several over 2,500 — and fast, cold descents into the next valley. The riding is on paved roads, non-technical, but relentlessly demanding, with high-altitude weather that can turn from heat to cold and storm quickly.

The landscape shifts from northern lakes and glaciated passes to southern, sun-baked Provence. This is for fit, experienced road cyclists who love climbing; the passes, not the distance, define the effort.

Ride it in summer, roughly June to September, once the high passes — the Iseran and Galibier in particular — are clear of snow and open. Go south from Thonon-les-Bains to Menton to finish at the sea, over about eight days, though strong riders do it faster.

It's self-guided on open roads, so plan accommodation and resupply in the valley towns between passes, and consider luggage transfer to ride light. Come with real climbing fitness and low gearing; carry layers and a rain shell for the cold, exposed cols.

Check pass opening dates before you set out, and start each big climb early to avoid afternoon storms.