Bocchetta del Croso

Overview

Bocchetta del Croso is a genuine hors catégorie (HC) test, the hardest rating a climb can carry. Over 25.3 km it drags you from a valley floor at 347 m up to a 1936 m summit — a net elevation gain of 1589 m at an average gradient of 6.29%. That average sounds civil, but averages lie on climbs this long: buried inside is a savage 28.85% maximum ramp that will empty your legs if you meet it unprepared. This is an endurance climb first and a strength climb second, and both accounts get called in before the top.

How the Gradient Unfolds

A 6.29% average across 25.3 km tells you the workload is sustained rather than explosive — but the 28.85% spike tells you it is not evenly spread. The total ascent of 1548 m sits just under the 1589 m net gain, meaning the road climbs almost continuously with only trivial dips; there is very little free downhill recovery to bank on. Expect long stretches sitting near or just above the average, punctuated by steeper pitches that push well into double digits. The 28.85% wall is the single moment that dictates everything: it is far steeper than anything you can grind through on momentum, so you must arrive at it with reserves rather than already redlined.

Pacing Notes

On a climb this long, discipline beats bravado. Anchor your effort to a percentage of your FTP — for most riders, settling into a steady tempo you can hold for well over an hour is the only way to survive 25.3 km without blowing up. If you do not know your threshold, run the numbers through the FTP estimator before you tackle it, then hold a touch below that line for the bulk of the climb. Save a real match for the 28.85% ramp: on gradients that steep, cadence collapses and the effort briefly surges regardless of pacing plan, so bank the headroom in advance rather than trying to recover mid-wall.

Gearing

Gear for the wall, not the average. A 6.29% mean is manageable on modest ratios, but 28.85% will humble anything too tall. For most riders a compact 34-tooth chainring paired with a wide cassette is the sensible floor. A 34×32 will get many trained riders over the top, but on a 25.3 km climb with a near-30% pitch and 1589 m to gain, the extra insurance of 34×34 is worth carrying — that lower gear preserves cadence and spares your knees when fatigue arrives late. If your setup allows an even easier bailout, you will not regret it here.

Summary

Bocchetta del Croso earns its HC status honestly: long, relentless, and topped with a ferocious 28.85% sting. Pace to your threshold, gear for the wall, and respect the full 25.3 km, and the 1936 m summit is yours.

Length: 25.3 km
Average gradient: 6.29%
Max gradient: 28.85%
Start: 347 m
Summit: 1936 m
Net gain: 1589 m
Total ascent: 1548 m
Category: HC