Colletto del Lago

Overview

Colletto del Lago is a genuine hors catégorie (HC) test — the hardest classification on the scale, sitting above categories 1 through 4. Over 13.9 km it averages 8.54%, hauling you from a start elevation of 1081 m up to a summit at 2271 m. That is a net elevation gain of 1190 m, with 1183 m of that as pure total ascent, so this is a near-continuous drag with almost no giveback along the way. The peak pitch of 15.71% tells you the climb does not settle into a comfortable rhythm; it keeps threatening to buck you off.

How the Gradient Unfolds

An 8.54% average across 13.9 km is already brutal, but averages hide the story. The gap between the 8.54% mean and the 15.71% maximum is roughly 7 percentage points, which means the steep ramps are nearly twice as hard as the "easy" stretches. With total ascent (1183 m) sitting only 7 m below net gain (1190 m), there is essentially no descending or flat recovery baked into the profile — every metre you gain, you keep. Practically, that means the climb is front-to-back effort: expect sustained grinding in the 8–9% band punctuated by sharp kicks reaching toward 15.71%. Save nothing for a false summit, because starting at 1081 m and topping out at 2271 m, the thin air near the top will bite exactly when the road refuses to flatten.

Pacing Notes

On a climb this long and steep, pacing is everything. Ride the whole 13.9 km at or just below your FTP — the power you can hold for roughly an hour — and treat the 15.71% ramps as brief surges you absorb rather than attack. Going into the red early, before you have climbed even a fraction of the 1190 m ahead, is the classic way to blow up. If you are not sure what your sustainable number is, run it through the FTP estimator before you go, then set a ceiling and hold it. On the steepest pitches, let your cadence drop and your speed bleed rather than spiking wattage; you have too much climbing left to spend matches here.

Gearing

For an HC climb averaging 8.54% and spiking to 15.71%, gear low and gear again. A compact 34-tooth chainring is the sensible front. Pair it with a wide cassette: 34×32 is the minimum I would bring, and on the 15.71% ramps at altitude near the 2271 m summit you will be grateful for anything easier. If your legs or your day are in question, fit 34×34 — the extra sprocket lets you keep spinning instead of grinding to a standstill on the worst kicks. Undergearing a 1190 m climb turns a hard day into a survival march.

Summary

Colletto del Lago is an HC monster: long, steep, and relentless from bottom to top with no recovery built in. Respect the average, fear the maximum, and gear conservatively.

Length: 13.9 km
Average gradient: 8.54%
Max gradient: 15.71%
Start: 1081 m
Summit: 2271 m
Net gain: 1190 m
Total ascent: 1183 m
Category: HC