The Mortirolo from Mazzo di Valtellina is 7.7 miles (12.4 km) at an average of 10.5%: 4,265 ft (1,300 m) of climbing, from 1,811 ft (552 m) to 6,076 ft (1,852 m). The databases agree closely: salite.ch gives 7.7 miles (12.4 km) and 4,265 ft (1,300 m); CyclingUp, 7.6 miles (12.3 km) and 4,281 ft (1,305 m); and CyclingCols, 7.5 miles (12.1 km) and 4,308 ft (1,313 m).
The climb, section by section
- First 2.2 miles (3.5 km), about 8%. The “easy” part, which is already harder than the average of many Alpine climbs.
- Kilometers 3.5 to 8.5 (13%). Three miles (5 km) straight at 13%, with the hardest kilometer at 15% and ramps of 17%. CyclingCols gives 12.8% for its steepest 5 km. This is the section that made the climb famous.
- Last 2.4 miles (3.9 km), about 9.7%. They start at the Pantani monument, at hairpin 11. A little less steep, but your legs are already battered.
The central section is confirmed by CyclingUp and CyclingCols; the last one comes from CyclingUp, and the first is what’s left to make up the total. The usual finish is the Passo della Foppa (6,076 ft / 1,852 m); the Passo del Mortirolo proper (6,220 ft / 1,896 m) is about half a mile (1 km) farther.
Its Giro d’Italia history
The Giro first climbed it on June 3, 1990, from Monno (the easy side), with Leonardo Sierra first to the top. Its great day came on June 5, 1994: on the Merano-Aprica stage, 24-year-old Marco Pantani attacked on the Mortirolo, dropped Miguel Induráin and race leader Evgeni Berzin, and won in Aprica. Since 2006 there’s been a monument to Pantani on the climb, and many call it “Cima Pantani.”
The Giro had climbed it 17 times through 2025. Riders first over the top include Franco Chioccioli (1991), Ivan Gotti (1996 and 1999), Ivan Basso (2006 and 2010), Giulio Ciccone (2019) and Afonso Eulálio (2025). The benchmark time is disputed: the Giro credits Gotti with 42:40 in 1996, but other sources give that time to Pantani in 1994.
When to go, water and traffic
The road is narrow, with so-so pavement and little traffic. Some summer mornings it’s closed to cars as part of the Enjoy Stelvio Valtellina program (for example, August 28, 2026, from 8:30 a.m. to noon). There’s a bar at the top. Other sides: Tovo di Sant’Agata (7.6 miles / 12.2 km at 10.7%), Grosio (9.2 miles / 14.8 km at 8.3%), Monno (6.6 miles / 10.7 km at 7.5%) and Edolo (10.7 miles / 17.2 km at 6.7%).
What gearing to use
No debate here: 34x34 or easier. At 3 W/kg (watts per kilo of body weight) and 159 lb (72 kg), you’ll ride about 4.3 mph (7 km/h) on 13%; with a 34x34 that’s about 56 rpm, and on the 17% ramps you drop to 43 rpm. With less power, a 32x36. Run the numbers in the gear calculator.
Tips
- The first 2.2 miles are already hard: don’t ride them flat out.
- On the 3 miles at 13%, find a pace you can hold for 40 minutes.
- Descend via Monno or Edolo, which are much gentler.
Frequently asked questions
How long does it take to climb the Mortirolo from Mazzo?
A 159 lb (72 kg) rider on a 21 lb (9.5 kg) bike takes about 1 h 27 min at 3 W/kg (216 W), 1 h 44 min at 2.5 W/kg and 1 h 06 min at 4 W/kg. Work out your own time with your weight and power in the calculator on this page.
What is the steepest grade on the Mortirolo?
17%, according to CyclingCols and CyclingUp. The Giro and other websites talk about 18-20%, but the databases that measure the climb give 17%.
Where is the Pantani monument on the Mortirolo?
Around kilometer 8 (mile 5) of the climb from Mazzo, at hairpin 11, where the last 2.5 miles (4 km) begin.
What is the record up the Mortirolo?
Sources disagree: the Giro credits Ivan Gotti with 42:40 in 1996, while others give that time to Pantani in 1994. That's why we don't list it as a record.