Passo Pramosio

Overview

Passo Pramosio is a full-length mountain ascent, and its numbers leave no doubt about the category: 21.3 km at an average of 6.5%, rated HC — hors catégorie, the hardest classification there is. From a start elevation of 419 m, the road works its way up to a summit of 1805 m, a net gain of 1386 m over its length. The total ascent registers at 1375 m, so there is very little false-flat or descending relief hidden inside the climb — almost every metre you gain, you keep.

At 21.3 km, this is a climb measured in the better part of an hour, not minutes. It rewards riders who can settle into a rhythm and hold it, because the length punishes anyone who starts too hard.

How the Gradient Unfolds

A 6.5% average is deceptive on a climb this long. The maximum gradient of 28.06% tells you the road is far from uniform: for a pitch to reach more than four times the average, there must be sections that ease off to balance it out. Expect the ascent to breathe — steeper walls that spike well into the twenties, separated by stretches that sit closer to, or below, the 6.5% mean.

The gap between the 1386 m net gain and the 1375 m total ascent is small, confirming that the road climbs relentlessly rather than rolling. When you do the arithmetic on the two figures, the difference of 11 m is essentially noise: this is a climb that goes up and stays up. Plan for the ramps, not the average.

Pacing Notes

On a 21.3 km HC climb, pacing is everything. Your target should be a sustainable effort anchored to your FTP — the power you can hold for around an hour. Given the length, most riders will spend the climb at or just below threshold, leaving headroom to absorb the steep pitches without going into the red.

If you do not know your threshold number, run it through the FTP estimator before you commit to a pacing plan. The steep sections that approach 28.06% will spike your power far above target; the key is to accept those brief surges and return to your steady effort immediately afterward rather than chasing the number back down all at once.

Gearing

With a maximum gradient of 28.06% and 21.3 km of climbing in your legs, gear low and gear generously. A compact 34-tooth chainring is the starting point. Pair it with at least a 34×32 for the sustained 6.5% stretches, and strongly consider a 34×34 to give yourself a bailout cassette sprocket for the near-28% walls.

On a climb gaining 1386 m, cadence preservation matters more than pride. The difference between 34×32 and 34×34 is the difference between grinding and spinning when the road kicks up late — after 1805 m of elevation is under you, you will want the easier option.

Summary

Passo Pramosio is a true HC endurance climb: long at 21.3 km, steady at 6.5% on average, and brutal in its steepest pitches at 28.06%. Pace it to your threshold, gear low, and respect the 1386 m of vertical between the 419 m base and the 1805 m summit.

Length: 21.3 km
Average gradient: 6.5%
Max gradient: 28.06%
Start: 419 m
Summit: 1805 m
Net gain: 1386 m
Total ascent: 1375 m
Category: HC