Colma del Bugone

Overview

Colma del Bugone is an HC climb — hors catégorie, the hardest rating there is — and the numbers explain why in a single glance. Over 9.7 km the road hauls you from 209 m to 1143 m, a net gain of 934 m, with the recorded total ascent sitting at 913 m. The average gradient is a savage 9.62%, and the road bites back with ramps as steep as 13.46%. There is nothing gentle here: almost the entire climb sits above the pitch most riders would call "hard," and the summit arrives only after you have paid for every one of those metres.

How the Gradient Unfolds

The defining feature of Bugone is its relentlessness. With a 9.62% average sustained across the full 9.7 km, there is no meaningful recovery built into the shape — you do not so much climb it as endure it. The gap between the 9.62% average and the 13.46% maximum is smaller than on many long passes, which tells you the hard sections are not brief spikes but a consistently steep wall. Expect the gradient to hover near double digits for long stretches, tipping toward that 13.46% ceiling on the worst pitches. The near-vertical relationship between the 934 m of net gain and the modest 9.7 km horizontal distance is the whole story: steep, and steep the whole way.

Pacing Notes

On a climb this uniformly steep, pacing is survival. There are no flat sections to soft-pedal and recover, so the effort you settle into early is very close to the effort you will hold for the full 934 m of ascent. Anchor your pace to your FTP: on an HC effort of roughly 9.7 km at 9.62%, most riders will spend the entire climb near or just under threshold, because the gradient never lets power drop. Start conservatively — the temptation to push on the lower slopes is punished later when the road refuses to ease. If you do not know your threshold number, run yours through the FTP estimator first, then translate it into a target you can actually hold from 209 m all the way to the 1143 m summit.

Gearing

Do not under-gear this one. With a 9.62% average and pitches to 13.46%, gearing is the difference between spinning and grinding to a halt. A compact 34-tooth inner ring is the baseline, and it needs a wide cassette behind it. A 34×32 is the minimum most fit riders should bring; on a sustained 9.62% wall it gives you a fighting cadence without cross-chaining into the very bottom sprocket too early. If you weigh more, are carrying fatigue, or simply want to protect your knees over 9.7 km of climbing, step up to 34×34 — the extra range keeps your cadence civilised when the road hits 13.46%. Easier is almost always the right call on an HC climb.

Summary

Colma del Bugone is a pure HC grind: short in distance, merciless in gradient, and unforgiving from bottom to top. If you respect the pacing and bring enough gear, the 934 m of climbing is a rewarding — if painful — day out.

Length: 9.7 km
Average gradient: 9.62%
Max gradient: 13.46%
Start: 209 m
Summit: 1143 m
Net gain: 934 m
Total ascent: 913 m
Category: HC