While the TMB doesn’t climb to the summit of Mont Blanc, the route climbs up and over numerous high alpine passes, providing stunning views in all directions! Thanks to a well-developed system of huts, along with towns and hotels along the route, there are numerous options for staying overnight and resupplying as you journey around the loop.

Unlike the hiking version of the TMB, the mountain biking version of this route isn’t nearly as well defined. Instead, riders can choose from numerous route variants. For this variant we tried to optimise for maximum time in the saddle, and minimum time carrying your bike. This means the tour has several longer segments of paved road, particularly on the climbs.

Start in Chamonix, and head northeast through the valley past Agentiere and on to Le Tour. Here you'll start the first long climb to the first pass at Col de Balme. This is also the border to Switzerland—make sure you have your passport!

The first big descent is a very rocky singletrack. There are some tight hairpin turns and exposed sections. Watch out for a couple of steep steps.

At the bottom you'll have a short flat ride through the valley, passing to the east of the small village of Peuty. From there you'll start the next shorter climb to Col de la Forclaz. Stop here for a snack and a drink before continuing the descent on the road to Les Rappes. There's a few sections of offroad singletrack on the way down, or you can stick to the road if you're feeling tired.

From the bottom you'll start your last long climb to Champex. This one is about 1000m of vertical, all on the road. It's a rather long, unforgiving climb, especially on a mountain bike—but the view of the lake at the top is worth it!

Sources: https://en.wikipedia.org/wiki/TourduMontBlanc