Passo del Sasso Nero

Overview

Passo del Sasso Nero is a hors catégorie (HC) climb, the hardest classification on the road-cycling scale before you drop back to category 1. It stretches for 28.3 km and gains a net 1870 m, lifting you from a valley floor at 468 m all the way to a 2338 m summit. The average gradient of 6.62% sounds civilised, but across nearly thirty kilometres that number represents a relentless, sustained effort rather than a short, sharp shock. With a total ascent of 1861 m recorded over the profile, this is a climb measured in hours, not minutes, and it rewards patience far more than aggression.

How the Gradient Unfolds

The headline figure is the 6.62% average, but averages hide the story. A max gradient of 26.97% tells you there is at least one wall on this road that will force you out of the saddle and into your easiest gear. Because the mean sits at 6.62% while the peak spikes to nearly 27%, you should expect the climb to breathe: stretches noticeably shallower than the average that let you recover, offset by pitches that ramp well into double digits. Over 28.3 km the cumulative demand is what defines the climb — every gentle section is effectively borrowed time you repay on the steeper ramps. Read the road ahead, and treat any easing as a chance to eat, drink and settle your rhythm before the gradient bites back.

Pacing Notes

On a climb this long, pacing is everything. Anchor your effort to your FTP and aim to sit just below it for the sustained sections, leaving headroom to absorb the steep pitches toward that 26.97% max without blowing up. A useful target is a steady, conversational-to-firm tempo that you could hold for the full 28.3 km rather than a pace that feels comfortable only in the first few kilometres. If you are unsure of your current threshold, run the numbers through the FTP estimator before you commit to a pacing plan. Going out too hard on the lower slopes is the classic error here — with 1870 m of climbing ahead, the mountain always collects its debt in the final third.

Gearing

Gear for the steep ramps, not the average. Given the 26.97% max gradient and the sheer duration, most riders should treat a compact 34-tooth chainring paired with a wide cassette as the baseline. A 34×32 is the minimum I would recommend for tackling the harder pitches with your cadence intact, and if you have it, a 34×34 gives you meaningful extra insurance for the steepest walls near that near-27% figure. On a 28.3 km effort, spinning a slightly easier gear preserves your legs for the top far better than grinding.

Summary

Passo del Sasso Nero is a proper HC test: long, high, and steep enough in places to demand respect and the right gearing. Pace it off your threshold, save something for the ramps, and let the summit come to you.

Length: 28.3 km
Average gradient: 6.62%
Max gradient: 26.97%
Start: 468 m
Summit: 2338 m
Net gain: 1870 m
Total ascent: 1861 m
Category: HC