Relentless steep climb
Sustained double-digit gradients with little rhythm or relief
The Mortirolo Pass (1,852 m) connects Valtellina to the north and Val Camonica to the south. It is a climb defined not by a single moment, but by what it never stops doing.
The Mortirolo doesn’t build gradually or reveal a decisive section near the summit. From early on, the gradient rises into double digits — and stays there for most of the ascent.
What makes it distinctive is the continuity of that effort:
- long stretches above 10%
- frequent ramps pushing well beyond that
- only brief variations that never amount to real recovery
Even where the road changes slightly, it does so within a narrow range: steep to very steep, rather than difficult to manageable
The setting reinforces that character. Much of the climb runs through narrow, wooded sections, limiting exposure and keeping the focus on the effort itself rather than the landscape.
This is not a climb that develops, it is one that establishes its difficulty early and maintains it throughout.
Why ride it
Because you enjoy suffering on a bike a good challenge. This is one of the few climbs where difficulty is constant rather than concentrated.
Most major climbs give you a structure:
- a rhythm to settle into
- a key section to prepare for
- or a final moment where the effort peaks
The Mortirolo does none of that.
Instead, it works through accumulation:
- gradients remain consistently high across most of the climb
- short variations interrupt rhythm without providing recovery
- steep ramps appear often enough to prevent any sustained pacing
Even where the slope eases, it rarely drops far enough to reset your effort.
It becomes a cycle of:
- managing steepness
- absorbing short changes
- and continuing without fully recovering
That gives the climb a very specific feel:
- pacing becomes uncertain
- effort is reactive rather than controlled
- and the challenge is as much mental as physical
Unlike other climbs:
- you don’t build into it
- you don’t wait for it to get harder
- you don’t time your effort around a key section
You are already in the hardest part — and stay there.
It works best as:
- a pure challenge climb
- something you ride to test your limits
- rather than for rhythm, scenery, or progression
The Mortirolo isn’t about when to push — it’s about how long you can sustain it
Giro d’Italia
The Mortirolo featured 17 times in a Giro d’Italia stage between 1990 and 2025. The Monno ascent was included 5 times, the Mazzo ascent 11 times and the Tovo di Sant’Agata ascent once.
The Mortirolo’s Mazzo ascent in the Giro made such a name, that the Vuelta felt the need to respond and find something harder and as a result, the Angliru was introduced.
Not in the least disheartened, the Giro retaliated by introducing the Monte Zoncolan…
Cima Pantani and Pantani Memorial
Since the death of Marco Pantani in 2004, stages of the Giro that go over the Mortirolo feature a special prize. This is called the Cima Pantani, awarded to the first rider at the summit.
Taking this one step further in 2024, local authorities changed the official name of the pass to Cima Pantani.
One of the many monuments1 to commemorate Marco Pantani is on the Mortirolo. Erected in 2006, high on a wall in hairpin 11 of the Mazzo ascent, the sculpture shows Pantani in his classic attacking position. He’s looking back over his left shoulder, smiling, assessing the damage he’s done.
The approaches
The Mortirolo can be climbed from multiple sides, but they do not offer the same experience.
All routes are demanding, what changes is how quickly the steepness arrives — and how long it is sustained.
From Mazzo di Valtellina
The most defining approach.
- The climb steepens early and settles into double-digit gradients
- A long central section sustains very high gradients, often above 13–14%
- Variations exist, but rarely allow meaningful recovery
This is the version that defines the Mortirolo:
Difficulty appears early and remains present for most of the ascent
It’s during this climb that you will pass the Pantani monument in hairpin 11, about four kilometers from the summit.
Bonus: the less travelled ascent from Mazzo, via the Via Orti, is even harder than this one: 11.3 kilometers at 11.6%.
From Tiolo
A more progressive version of the climb’s defining character.
- Accessed via the signed turnoff near Tiolo
- The climb builds more gradually than the Mazzo approach
- The steepest sections arrive later, rather than immediately
Once the road settles into the main ascent:
- gradients still rise well into double digits
- sustained steep sections remain a defining feature
- variation exists, but recovery is still limited
The same overall difficulty is present, but the way it develops is less abrupt.
This creates a different experience:
- less immediate pressure
- more time to establish effort
- but ultimately the same requirement to sustain steep climbing
Still a true Mortirolo ascent — just without the same early intensity
Note that while this is labeled “from Tiolo” it is often also referred to as “from Grosio”, as this approach starts between the two. The other Grosio route up the Mortirolo is a little harder to find:
- Follow the main road until you pass the Grosio city sign and then turn left towards Sondrio
- After some 500 meters, there’s a narrow bridge on your left, the start of this Mortirolo route
- About 1 kilometer in, there’s a bifurcation: turning left will join the Tiolo route, so keep right for this Grosio route
Both alternatives join the one from Mazzo at hairpin 8, some 3 kilometers before the summit.
From Edolo
The most regular and least extreme approach.
- Lower average gradients
- Longer sections at manageable effort
- Fewer extended double-digit ramps
A different experience to the same summit, without the same defining steepness
Bonus: there is a harder alternative, taking the Recta Contador or Vecchia Mulattiera, the old mule track. It parts the classic route just outside Monno in hairpin 12 and rejoins it before hairpin 10.
It is by itself only 3 kilometers long, averaging 13.7%, hitting 21.6% along the way and it shortens the Monno route to 14 kilometers.
What stays consistent
Across all approaches:
- gradients are high compared to most alpine climbs
- recovery is limited
- effort remains continuous rather than sectional
But:
- only one route delivers that intensity from early on
- the others approach the summit with a more gradual build
The Mortirolo isn’t about timing your effort — it’s about enduring it
Bike Rebel and the Mortirolo
I only managed to not nearly give up once: the first time I tackled the Mazzo ascend in 2011. I choked on the Mazzo (2019 and 2020) and Tiolo (2020) sides since then.
My first Monno ascend of the Mortirolo was in 2015 and I revisited it in 2020, stage 4. This ascent is doable, even for me 🙂
I have uploaded a few videos of the Mortirolo to my YouTube channel and to my Kinomap channel, where you can cycle them indoors yourself.
1 I don’t know how many “Pantani Forever” monuments there actually are, but I’ve cycled passed five of them so far: this one, on the Fauniera, the Galibier, les Deux Alpes and Montecampione.
