Mortirolo from Mazzo: 12 km at 10.5% and no easy kilometre

The Mortirolo is not high, not long and not pretty in the postcard sense. It is just relentlessly steep. From Mazzo di Valtellina the Giro d'Italia gives it 12.5 km at an average of 10.5%, with ramps of 20%, almost all of it in the woods, where you cannot see what is coming. It is the climb where Marco Pantani made his name in 1994, and it is still the one most amateurs talk about with something close to fear. Here is how the climb is built, how to get up it without walking, and how to fit it into a ride.

The climb: no easy kilometre

The Lombardy Region's tourism site puts the climb at 12.4 km from Mazzo at 552 m to the pass at 1,852 m, a gain of 1,300 m. Our track starts in the village and is a little shorter, 11.3 km with 1,299 m of climbing, which makes its average steeper still: 11.5%. Either way, this is what matters: on our track not a single kilometre averages under 8%.

• The first four kilometres. It starts hard and stays hard. Our track has 15.1% between km 1 and 2 and 14.7% between km 3 and 4, with nothing easier than 10.5% in between. There is no warm-up, so do it before you reach Mazzo.
• Past San Matteo. The regional tourism site says the hardest section starts after about 4 km, once you leave the church of San Matteo behind, and that this is where many riders have to put a foot down. On our track km 4 to 8 average about 12%, with 13.3% and 13% in the steepest kilometres, and short ramps a lot steeper than that.
• The Pantani monument. At the 8th kilometre stands the sculpture of Pantani, placed in 2006 at the spot known as Piaz de l'acqua. It is also roughly where the worst is over: after it the gradient drops to between 8 and 10%.
• To the pass. The last three kilometres are "only" 8–10%. After what you have just climbed, they feel almost kind. The woods open into a broad basin of meadows below the pass.

How to get up it

On a climb this steep, pacing by power is less about a target than a ceiling. The gradient will push you over threshold whatever you do. Your job is to stop it pushing you far over.

• Gear before anything else. On 13–15% a 34×28 forces most amateurs into a 50 rpm grind. A 34×34, or a 32 or 30 chainring with a big cassette, keeps your cadence in the 60s. Our guide to gearing for climbing covers the options.
• Set a ceiling, not a target. Decide in advance that you will not ride above about 95% of FTP for more than a minute, and sit up a little on the steepest ramps rather than sprinting them. Riders who chase the ramps in the first four kilometres are the ones walking after San Matteo.
• Mix sitting and standing. Stand for the steepest ramps to use different muscles, then sit back down as soon as the road eases. Seated vs standing climbing explains when each pays.
• Heat and fuel. The climb starts in the bottom of the Valtellina, low enough to be hot on a summer afternoon, and you will be moving slowly in the woods with little cooling air. Start early, carry two bottles, and eat something in the first half-hour; it is hard to eat on 14%.

From back road to battlefield

For most of its life the Mortirolo was a minor mountain road. According to Italia.it it was long unpaved and known as the Passo della Foppa. Its fame began when the Giro d'Italia included it in 1990, from the gentler Edolo side. Leonardo Sierra was first over the top and won the stage, the first Venezuelan to win a stage of the Giro. From 1991 the race used the Mazzo side, which the Giro now calls the traditional one.

In 1994, on the stage from Merano to Aprica, Marco Pantani attacked on the Mortirolo, dropped Miguel Indurain and won alone in Aprica. The sculpture at the 8th kilometre remembers that ride. The climb has been a decisive one ever since. In 2019 Giulio Ciccone was first over the top and won the stage to Ponte di Legno.

Planning the ride

• Getting there. Mazzo is in the Valtellina between Tirano and Bormio. Ride in from either town to warm up properly before the first ramp.
• The descent. Over the top, the road drops to Monno and Edolo in Val Camonica. We would not descend the Mazzo side: it is steep enough to overheat rim brakes and test anyone's nerve. If you must, read descending faster and safer first.
• The big loop. The Bormio tourist board describes a loop from Bormio to Mazzo, over the Mortirolo to Edolo and Ponte di Legno, then over the Gavia and back to Bormio. It estimates nine hours forty minutes and recommends it only for experienced, well-prepared riders.

Ride it in Moveee Indoor

The route on this page is the real road from Mazzo to the pass, with its height at every point. In Moveee Indoor your smart trainer reproduces that gradient, and the world around you is built from map data of the real place. On the Mortirolo that is exactly what you want to rehearse: an hour or more at 11–15%, at a cadence you probably never ride at home. Ride it indoors with the gearing you plan to take, and you will know before the trip whether it is low enough.

The ride is saved with its power data, so you can see whether you stayed under your ceiling or blew up after San Matteo. It works in the browser and in the Mac and Windows apps. To ride it in another app, download the GPX above.

The short version

About 12.4 km and 1,300 m from Mazzo to 1,852 m, at an average over 10.5% and with ramps of 20%. There is no easy kilometre until the Pantani sculpture at km 8, so warm up before Mazzo, fit the lowest gear you can and ride to a ceiling, not a target. Descend to Monno, not back the way you came.