Passo del Lago

Overview

Passo del Lago is a hors catégorie (HC) climb — the hardest classification on the scale before category 1, 2, 3, and 4 — and it earns the label without any argument. Over 14.3 km the road climbs from 432 m to a summit of 1863 m, a net elevation gain of 1431 m at a punishing average gradient of 10.02%. That combination of length and steepness is what separates HC ascents from everything below them. This is not a climb you survive by momentum; it is a sustained, hour-plus effort where the gradient rarely relents and the summit feels genuinely earned.

How the Gradient Unfolds

A 10.02% average across 14.3 km tells you almost everything: there is no long false-flat to hide in and no gentle run-in to warm the legs. With a maximum gradient of 20.32%, the hardest ramps are more than double the average, and those pitches are where races are won and where riders come undone. The total ascent of 1369 m sits just below the net gain of 1431 m, which means the profile is almost relentlessly upward — very little descending or flat to break the rhythm. Expect the steepest sections to arrive as sharp spikes stacked on an already-severe baseline, so the climb feels less like a single wall and more like a staircase that keeps tilting.

Pacing Notes

On a climb this long and steep, pacing is everything. Set your effort against your FTP and hold something in reserve for the 20.32% ramps, where power spikes are unavoidable. A common mistake is attacking the lower slopes at a pace the full 14.3 km simply will not allow. Aim to ride the average gradient at a controlled, repeatable output and treat the maximum-gradient pitches as short surges rather than sustained efforts. If you are unsure what number to target, use the FTP estimator to anchor your goal wattage before you start, then discipline yourself to sit just under it until the final kilometres.

Gearing

Gear for the steep pitches, not the average. With a 10.02% mean and ramps to 20.32%, most riders will want the widest range they can fit. A compact 34-tooth chainring paired with a 34×32 cassette is a sensible floor for strong climbers, but many will be far happier — and far fresher near the 1863 m summit — running 34×34. The extra range keeps your cadence up on the maximum-gradient sections and protects your legs across the full 1431 m of climbing. If your setup allows even more range, take it; nobody regrets an easier gear on an HC ascent.

Summary

Passo del Lago is a complete HC test: long, unrelentingly steep, and topped off with double-digit ramps that punish any pacing error. Gear conservatively, set your effort by FTP, and respect the full 14.3 km.

Length: 14.3 km
Average gradient: 10.02%
Max gradient: 20.32%
Start: 432 m
Summit: 1863 m
Net gain: 1431 m
Total ascent: 1369 m
Category: HC