Colletto di Valscura

Overview

The Colletto di Valscura is one of those climbs that leaves no room for negotiation. Over 18.2 km it averages a savage 10.06%, hauling you from a start elevation of 777 m all the way up to a 2603 m summit. That is 1826 m of net gain and 1810 m of total ascent — the two figures sit almost on top of each other, which tells you this road climbs and keeps climbing, with almost no false flat or descent to break the rhythm.

Its HC (hors catégorie) rating is fully earned. A double-digit average sustained across more than eighteen kilometres is the kind of number that separates HC efforts from category 1 climbs. This is a summit to respect long before you turn the pedals.

How the Gradient Unfolds

The defining feature of the Valscura is relentlessness. With net gain (1826 m) and total ascent (1810 m) nearly identical, the profile is essentially monotonic — the road goes up, then up some more. There are no recovery descents banking free metres and no long plateaus to spin the legs loose.

At 10.06% average across 18.2 km, even the "easier" stretches will still be climbing hard. Expect the gradient to hover around and above that mean for long, unbroken sections. Because there is no published max gradient, treat the average as your planning anchor and assume the steepest ramps sit meaningfully above 10%. The altitude also matters: finishing at 2603 m means the final kilometres come with thinner air, so the last third feels harder than the numbers alone suggest.

Pacing Notes

On a climb this long and steep, pacing discipline is everything. Ride the first few kilometres well within yourself — the temptation to match the gradient with matching aggression is how riders blow up before halfway.

Anchor your effort to your FTP. A sustained 18.2 km ascent at 10.06% is a threshold-or-below test of durability, not a punchy VO2 effort, so hold a power you can defend for well over an hour. If you are unsure of your number, run the FTP estimator before you commit to a target and give yourself a small buffer for the altitude near the 2603 m summit.

Gearing

Do not under-gear this one. With a 10.06% average sustained over 18.2 km, a 34×32 is the sensible floor for strong climbers, and many riders will be far happier with a 34×34. The extra sprocket buys you a lower cadence option on the steepest ramps and preserves your legs across the full 1826 m of gain.

If your bike allows a wide-range cassette or a sub-compact chainring, use it. Spinning a manageable cadence beats grinding, especially with the thin air waiting at 2603 m.

Summary

The Colletto di Valscura is a true hors catégorie test: 18.2 km, 10.06% average, and 1826 m of near-continuous climbing to a high summit. Pace it patiently, gear it generously, and respect the altitude.

Length: 18.2 km
Average gradient: 10.06%
Max gradient: n/a
Start: 777 m
Summit: 2603 m
Net gain: 1826 m
Total ascent: 1810 m
Category: HC