Just so you can see it, I rode some of the etape 2010 route on Sunday – and on a bike with a Garmin Edge 705. This also had a PowerTap wheel, and the following diagram shows you what you have to look forward to:
In this plot you can see we started some 5km from the start of the Col du Marie Blanque, which starts fine, but the last 5km is relentless. I got to rest at the top of each of these climbs, with hot coffee and biscuits, I suspect I won’t have that on the day.
There are a couple of cheeky climbs then on the way to the Soulour, and the Soulour is no mean mountain in itself, although preferable to the Marie Blanque. After the Soulour, it is all downhill to Arzeles-Gazost, from where the tailwind pushes you up the gorge towards the Tourmalet. It is between 3-5% uphill along that section, before you start the climb of the Tourmalet. After the village of Bareges, the stiff short climb is unwelcome, but thereafter it goes up the alternate route (across the car park and up the switchback track) to the top. I was lucky to have a cool day which was deteriorating to the extent that when I arrived at the top, the heavens started to open, my compatriots were not so lucky, Jon coming in some 30 minutes or so later, drowned…
One other thing, we drove the 50km or so to the bottom of the Marie Blanque, but it includes a few decent climbs – over 500m in all, so don’t hurry that section or you’ll doe before reaching the top of the Marie-Blanque, let alone completing the rest.