Colletto del Valasco

Overview

Colletto del Valasco is a hors catégorie giant — the hardest classification a climb can carry. Over 30.9 km it hauls you from a 500 m start to a 2344 m summit, a net elevation gain of 1844 m. The average gradient reads a deceptively modest 5.96%, but that number hides both the sheer distance and the pitches that spike to 15.2%. With 1822 m of total ascent packed into a single sustained effort, this is a climb measured in patience as much as power.

How the Gradient Unfolds

Averages lie on a climb this long. A 5.96% mean across 30.9 km means the road rarely lets you coast, yet also rarely settles into a single rhythm. The gap between the 5.96% average and the 15.2% maximum tells the real story: expect long stretches near the average punctuated by sharp ramps that force you out of the saddle or deep into your gears.

Because the net gain (1844 m) sits close to the total ascent (1822 m), there is almost no relief — no meaningful descents to recover on. The road climbs, and keeps climbing. The final approach to 2344 m also means thinning air, so the same wattage that felt manageable low down will cost you more near the top.

Pacing Notes

On a 30.9 km HC climb, discipline beats bravado. The single biggest mistake is chasing the steep 15.2% ramps early and paying for it across the remaining kilometres. Anchor your effort to your sustainable threshold rather than the gradient of the moment.

Ride the shallower sections just under your FTP, and let the power drift only slightly higher on the steepest ramps rather than surging hard. If you do not know your current threshold, run the numbers first with the FTP estimator so your target is grounded in real data, not guesswork. With 1844 m still to gain from the base, a steady negative-split mindset — conservative early, stronger late — will get you to the 2344 m summit intact.

Gearing

Gear for the distance and the ramps, not the average. On a climb topping out at 15.2% after 30.9 km of accumulated fatigue, most riders will want a compact chainring paired with a wide-range cassette. A 34×32 lowest gear is a sensible baseline for strong climbers who can hold a steady cadence. If you weigh more, ride at endurance level, or simply want insurance for the steep pitches this deep into a 1844 m ascent, step up to a 34×34 — the extra range keeps your cadence alive when the road bites and your legs are already deep into the effort.

Summary

Colletto del Valasco is a full HC test: long, relentless, and topping out high enough that altitude adds its own tax. Respect the 30.9 km, meter your effort against the 5.96% average, and gear low enough to survive the 15.2% ramps, and the 2344 m summit is within reach.

Length: 30.9 km
Average gradient: 5.96%
Max gradient: 15.2%
Start: 500 m
Summit: 2344 m
Net gain: 1844 m
Total ascent: 1822 m
Category: HC