Passo di Mortirolo is a high mountain pass at an elevation of 1.852m (6,076ft) above the sea level, located in the Alps in Italy. This legendary climb is one of the most demanding stretches of road in professional world of cycling having been used in the Tour of Italy stage race many times. The road includes grades up to 26%, is very narrow, without turnarounds and no 3-axle vehicles are permitted.
The asphalted road over the pass connects Mazzo di Valtellina and Val Camonica. The road from Mazzo di Valtellina is one of the most demanding climbs in professional road bicycle racing. Mortirolo is known as the hardest climb in Italy with average percentages over the 10%. There is little use in being subtle about such a tough climb. The Mortirolo is considered to be the toughest mountain one can climb in Italy and many professional cyclers consider it as the most difficult mountain to be climbed in any of the three major tours. Lucho Herrera (1991) referred to Mortirolo as being the "Queen climb of Europe" and Lance Armstrong referred to it as the hardest climb he'd ever ridden.
On older maps the pass is known as Passo di Foppa. The Mortirolo has featured in the Giro d’Italia several times, including in 1994, when the first rider over the summit was a 24-year-old Marco Pantani and that day is marked with a memorial of il Pirata on the climb. The Passo di Mortirolo is one of the most brutal climbs. This is the climbing! The most famous climbing in the world of cycling, the most loved, the most desired, the most feared.
There are several routes to reach the summit. Starting from Monno, the ascent is 9.61 km long. Over this distance, the elevation gain is 946 meters. The average percentage is 9.8%. The maximum slope is 26%. Starting from Edolo, the ascent is 17.2 km long. Over this distance, the elevation gain is 1.153 meters. The average percentage is 6.7%. Starting from Grosio, the ascent is 14.8 km long. Over this distance, the elevation gain is 1.222 meters. The average percentage is 8.3%. And starting from Mazzo, the ascent is 12.4 km long. Over this distance, the elevation gain is 1.300 meters. The average percentage is 10.5%. The maximum slope is 18%.
At the summit there's a very narrow road to Aprica. It's 28,5km long climbing up to Passo di Guspessa, Passo di Picco and Monte Padrio, also called Valico di Trivigno. It's extremely dangerous. It’s very irregular, asphalted and very steep with some stretches around 20%. Speed limit to 20 km/h. Trucks and semi trucks are forbidden. It’s closed in winters and was an old military track. It has very nice views.