This a long climb down from Sierre (560m) in Valais/Wallis up the Val d’Annivers, which is the last french-speaking valley while going eastward up the Valais valley. The climb is quite nice and somewhat easy on a regular gradient up on nice big serpentines at first, then the road becomes almost flat for a long time as you wind your way up the valley to Vissoie (1204m), where the second relentless part starts. Now it is steeper, but still on a good wide road up to Chandolin (1983m). In Chandolin there is no asphalt road continuing higher up, but you can climb much higher on a fair gravel road (gravel road quality change as we know).

I struggled walking with the bike up the hillside to meet the gravel road, but you should really descend a little on the asphalt road ahead in Chandolin and then cycle on the gravel road all the way. There were otherwise only on short little steepish ramp at Tsapé that posed any kind of problem cycling all the way to the Illpass top (which is a few metres below the height of the road) The gravel road continues and you could likely go up above 2500m without any problem unless snow is in the way. It is, however, beautiful enough at Illpass.