Nice find, I'll look out for it next time. I rode the same from Mazzo past Pantani monument till the pass, I then rode down to Ponte de Legno up the Gavia, it rained from the bottom of the Gavia all the way to the top (some sections are over 15%), virtually no traffic. Then it snowed at the top, shivering I entered the sole restaurant for some food and warmth around their Fire place, this was in the middle of the summer! After an hour I decended back into Bormio which has to be one the great fast decents around, onto Mazzo then climbed Mortirolo again. Ok, I started the Mortirolo fresh well you try and climb the 2nd time around after the Gavia, makes it twice as hard, simply brutal. I then came back down to Mazzo back to Bormio where I was staying.
If you want a harder climb, drive to Ascona in Switzerland on the Swiss Italian speaking side not far from Lake Como probably 3 hours drive from Bormio and climb "Largo di Naret" a hidden gem, most Northern Italian's and Swiss will tell you it's the hardest climb in Europe. You'll suffer beyond comprehension but be rewarded with a top mountain lake in one of the worlds beautiful places, highly recommended. Though be aware the climb is extremely steep and extremely hard and should be attempted when in good form! a 32km climb http://www.cycling-challenge.com/lago-d ... tyPhoto/1/
the grads don't look that daunting well I know the grads are much worse and the length of the climb is immense.