Passo della Mezzaluna

Overview

Passo della Mezzaluna is a proper hors-catégorie (HC) test — the hardest classification a climb can carry, sitting a full rung above category 1. Over 20.3 km it lifts you from a valley floor at 159 m to a summit of 1453 m, a net gain of 1294 m. The average gradient of 6.36% sounds civilised on paper, but at this length the sustained effort is what defines the climb rather than any single wall. With a total ascent of 1277 m recorded across the profile, there are enough small dips and false flats to keep the road from being a single unbroken drag — though never enough to let you truly recover.

How the Gradient Unfolds

The headline numbers tell a story of contrast. A 6.36% average across 20.3 km is relentless but rhythmic; the 15.49% maximum is where the climb bares its teeth. That spread — nearly 9 points between average and peak — means the road is not evenly pitched. Expect stretches sitting comfortably around the average punctuated by steeper ramps that spike toward that 15.49% figure. The gap between the 1294 m net gain and the 1277 m total ascent is small, confirming that this is an almost uniformly upward climb with only minor undulation. In practice, you climb, then you climb harder, then you climb some more.

Pacing Notes

On a climb this long, pacing discipline beats bravado every time. Anchor your effort to your FTP and hold something in reserve for the ramps toward 15.49%, where surging will cost you dearly across the remaining kilometres. If you don't know your threshold number, run it through the FTP estimator before you commit to a target. A sensible approach is to ride the 6.36% sections just below threshold and absorb the steep pitches by dropping cadence briefly rather than blowing your effort ceiling. With 20.3 km to cover, a steady, sustainable power output will get you to 1453 m faster than a heroic early pace you cannot hold.

Gearing

Gear for the steep spikes, not the average. The 6.36% mean is manageable on almost any setup, but the 15.49% ramps late in a 20.3 km effort are where under-gearing ends days. A compact 34-tooth chainring paired with a 34×32 low is the sensible minimum for most riders here. If you climb at a lower cadence, carry extra weight, or simply want to preserve your legs across the full 1294 m of gain, step up to a 34×34. The wider ratio costs you nothing on the flatter sections and buys precious spin room when the road tilts toward its maximum.

Summary

Passo della Mezzaluna earns its HC badge honestly: long, sustained, and steep in the wrong places. Respect the length, gear conservatively, and ride to your threshold rather than your ego.

Length: 20.3 km
Average gradient: 6.36%
Max gradient: 15.49%
Start: 159 m
Summit: 1453 m
Net gain: 1294 m
Total ascent: 1277 m
Category: HC