A great route up from Martigny, but why no carry on to Chamonix on the Franch side. The route down is equally as good and Chamnix is worth a visit in the Summer. (Just dont go between end September and mid November....very quite and getting ready for ski season)
A fantastic stretch of road. Never done it on a bike but have travelled it many many times in my campervan...... One day soon I will do it on two wheels - I know more or less every metre of that road and the film brings it all back. If you are close enough to do it, then do it. You wont regret it. Beautiful scenery and an involving road, beware on the descent if you suffer vertigo and make sure you pull over to actually appreciate the scenery.
The road from Chamonix to Martigny is very good. I particularly liked the Col de la Forclaz, but thought iy best on the way up from Martigny. Great cafe/bar/restaurant at the top of the Col.
Great route. Starting from Trieg the route is running through a forest. The road is small and can be busy. The way down to Martigny is awesome. Nice corners and great view.