Passo del Mortirolo
From Mazzo di Valtellina · 12.4 km · 10.5 % average
Photo (illustrative – not this climb): Photo: Raul Taciu raultaciu · CC0
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- Start
- Mazzo di Valtellina
- Summit
- —
- Distance
- 12.4 km
- Elevation gain
- 1,300 m
- Average gradient
- 10.5 %
- Maximum gradient
- 18 %
- Difficulty
- Extreme (FIETS 13.6)
The climb at a glance
Schematic A straight line at the average gradient – the real road is steeper in places and easier in others.
- Other sides: Grosio 14.8 km at 8.3 %, Edolo 17.2 km at 6.7 % (Wikipedia).
In the footsteps of the pros
- Giro d'Italia: first used on stage 15 of the 1990 Giro, climbed from Edolo (Wikipedia).
- Since 2004 the first rider over the top in the Giro takes the ‘Cima Pantani’ prize (Wikipedia).
How long might it take?
| Sustained power | ≈ Time |
|---|---|
| 2.5 W/kg | 1 h 43 |
| 3.5 W/kg | 1 h 14 |
| 4.5 W/kg | 59 min |
Estimate Physics model at constant power on a constant 10.5 % gradient: rider 75 kg, bike and kit 9 kg, rolling resistance 0.005, CdA 0.4 m², air density 1.1 kg/m³, 3 % drivetrain loss; W/kg relative to rider weight; no wind, no stops. Real times vary – this is not a standard.
Best season
High-mountain road: typically a summer and early-autumn climb – check pass opening before you travel.
Weather & altitude
Low enough that altitude itself is not a factor; heat and sun can be.
Surface & traffic
[PLACEHOLDER] Road surface, traffic and tunnels – to verify
Water & food
[PLACEHOLDER] Fountains, cafés and the last shop before the top – to verify
Descent
[PLACEHOLDER] Descent notes – surface, hairpins, cold. Always pack a layer.
Nearby climbs
- Passo di Gavia ≈ 18 km away (straight line)
- Passo dello Stelvio ≈ 33 km away (straight line)
- Furka Pass ≈ 149 km away (straight line)
Sources & verification
Data Figures copied from the sources listed, retrieved 14 Nov 2026. Published numbers differ with the exact start and finish – we show one sourced version. Exact start point and date of on-the-road verification: [PLACEHOLDER] to record.