Madriccio Pass
Very challenging itinerary if done completely by pedaling, possibly to be split into two days. If done by ebike or if you are very well trained, it can still be done in one day and fully pedaled, except for a few dozen meters before the pass, which is why it is called the highest bike pass in Europe.
Start from the village of Morter at the bottom of the Martello valley and take the bicycle path to Prato allo Stelvio (you can take the train if necessary). From Prato you climb by forestry to the Valnera hut, then descend to Solda along the technical trail.
From Solda go up to the Milano hut passing under the cable car, this road is very steep, but with a good workout you can ride (alternatively go up by cable car).
From the refuge you climb up to the pass, even in this section some people push and some manage to pedal to the top. At the pass the views are amazing of the Ortles and Grand Zebrü.
The descent is at times very technical but beautiful until the Corsi ref.
From here again not easy trail to the lake, then more trail.
When you get to the road, it is better to follow it for a couple of km, because the path is hardly cyclable, and then follow 36 down to the valley. If you still have strength, at the end do the trail past Obermontani Castle, a last treat for a spectacular route.