Passo di Rondenino

Overview

Passo di Rondenino is an HC climb — hors catégorie, the hardest rating on the scale before the numbered categories 1 through 4. Over 18.7 km the road lifts you from a start elevation of 247 m to a summit at 2033 m, a net elevation gain of 1786 m. The average gradient of 9.57% is the number that defines this ascent: it is brutally, unusually steep for a climb of this length. Most passes that break 2000 m do so over gentler slopes; Rondenino refuses to give you that mercy. With a total ascent of 1762 m recorded along the way, there is barely any respite built into the profile. This is a climb you commit to fully, or not at all.

How the Gradient Unfolds

The headline figure is a 9.57% average sustained across 18.7 km, which means the climb rarely dips into anything that feels like recovery. Do the arithmetic and the scale becomes clear: nearly ten metres of vertical for every hundred metres of road, repeated for the better part of nineteen kilometres. The maximum gradient bites at 17.92%, roughly double the average, so the steepest ramps hit almost twice as hard as the pain you have already normalised. Because the average sits so high, these spikes are not isolated cruelties — they rise out of terrain that is already demanding. Expect the road to hold you at a punishing pitch and then occasionally rear up beyond it. There is no long false-flat to hide in.

Pacing Notes

On a climb this sustained, discipline beats bravado. Anchor your effort to your FTP and hold a steady, repeatable power rather than chasing the early ramps. At a 9.57% average, going five percent too hard in the first few kilometres will cost you far more than that on the upper slopes, where the 17.92% pitches demand every watt you have left. If you do not know your threshold precisely, run the numbers through the FTP estimator before you plan your ride. Break the 18.7 km into manageable blocks, keep your cadence from collapsing on the steep ramps, and treat the summit at 2033 m as the finish line — not the false crests along the way.

Gearing

With an average of 9.57% and maximum ramps of 17.92%, gearing is not a luxury here — it is survival. A compact 34-tooth chainring is the baseline. Pair it with at least a 34×32 for the sustained sections, and if your legs or your ride goals lean toward endurance, step up to a 34×34 to keep your cadence alive when the road hits its steepest pitches. On 1786 m of climbing packed into 18.7 km, the extra range you carry is the difference between spinning and grinding to a stall. Err toward easier gearing than you think you need.

Summary

Passo di Rondenino is a genuine test: long, unforgivingly steep, and topping out high. Respect the 9.57% average, gear for the 17.92% max, and pace to the 2033 m summit.

Length: 18.7 km
Average gradient: 9.57%
Max gradient: 17.92%
Start: 247 m
Summit: 2033 m
Net gain: 1786 m
Total ascent: 1762 m
Category: HC