Colletto Fenera

Overview

Colletto Fenera is one of those climbs that leaves no room for negotiation. Over 11.1 km it averages a savage 10.95%, and it earns its HC (hors catégorie) rating the honest way: through relentless, unbroken steepness rather than a few isolated ramps. You start at 417 m and finish at 1634 m, a net gain of 1217 m. The total ascent registers 1184 m, meaning there is almost no false-flat or descending relief along the way — nearly every metre you climb, you keep. When a climb this long holds a double-digit average, the story is written in your legs long before the summit.

How the Gradient Unfolds

The defining feature here is consistency of pain. A 10.95% average across 11.1 km means there are no soft kilometres to recover in; if the road eases to single digits anywhere, it must pay that back with slopes well above the mean. The spike comes at 24.4% — a wall steep enough that momentum evaporates and the climb becomes a matter of turning the pedals over one stroke at a time. Because the net gain (1217 m) exceeds the total ascent (1184 m) only by the smallest of margins, you can trust that the gradient rarely relents. Treat the whole 11.1 km as a single sustained effort, not a series of discrete pitches.

Pacing Notes

On a climb of this severity, pacing discipline is survival. The temptation is to attack the lower slopes while your legs feel fresh, but at 10.95% average that enthusiasm is expensive. Anchor your effort to your FTP and aim to hold a steady percentage of it from the base, leaving headroom for the 24.4% pitch that will force a surge whether you want one or not. If you do not know your threshold, run the numbers through the FTP estimator before you commit — climbing 1217 m at this gradient without a power reference is guesswork you cannot afford. Ride the first few kilometres a touch below what feels sustainable; the summit at 1634 m is a long way up.

Gearing

Do not underestimate what 10.95% over 11.1 km demands of your drivetrain. A compact 34-tooth chainring paired with a 34×32 cassette is the practical minimum for most riders, and even then the 24.4% ramp will have you grinding. If you have the range, go to 34×34 — the extra sprocket buys you cadence and spares your knees over an ascent that gains 1217 m. Anyone carrying weight, riding tired, or targeting a comfortable tempo should default to the larger cassette without apology. On Colletto Fenera, spinning is not soft; it is smart.

Summary

Colletto Fenera is an uncompromising HC test: long, steep, and consistent from base to summit. Come with the right gearing, a paced effort keyed to your threshold, and respect for a 24.4% wall that punishes anyone who arrives over-cooked.

Length: 11.1 km
Average gradient: 10.95%
Max gradient: 24.4%
Start: 417 m
Summit: 1634 m
Net gain: 1217 m
Total ascent: 1184 m
Category: HC