Passo di Brealone

Overview

Passo di Brealone is a genuine hors catégorie test, the hardest classification on the road. Over 21.9 km it climbs from a valley floor at 399 m to a summit of 2117 m, a net elevation gain of 1718 m. The average gradient reads 7.83%, but that single figure hides a climb that spends almost its entire length above threshold-level steepness. With a total ascent of 1692 m recorded on the ground, this is an effort measured in the better part of an hour or more for most riders, not minutes. The thin air near the 2117 m summit only sharpens the challenge as the road pushes toward its high point.

How the Gradient Unfolds

The headline shape is relentless consistency punctuated by savage spikes. A 7.83% average across 21.9 km means there is almost nowhere to truly recover — the road just keeps tilting upward. What defines Brealone, though, is its maximum gradient of 21.9%. That ramp is more than double the average, a wall steep enough to force riders out of the saddle and into survival mode. Expect the pattern to swing between long stretches near the average and short, brutal pitches that spike toward that 21.9% ceiling. Because the net gain of 1718 m sits close to the total ascent of 1692 m, there is very little false descent to break the rhythm; nearly every metre you climb, you keep.

Pacing Notes

On a climb this long, discipline wins. Anchor your effort to your FTP and resist the temptation to chase the early slopes — 21.9 km is far too long to bluff. Aim to hold a sustainable percentage of threshold on the steadier sections and accept that the spikes toward 21.9% will briefly spike your power well above that number; the trick is letting the gradient ease afterward rather than pressing on. If you don't know your threshold, run the numbers through the FTP estimator before you commit to a target. With 1718 m of vertical to absorb, a rider who paces the first two-thirds conservatively will pass those who went out hard.

Gearing

Gear for the 21.9% maximum, not the 7.83% average. On a 21.9 km climb with pitches this steep, undergearing turns a hard day into a walk. A compact 34-tooth chainring paired with a 34×32 cassette is the sensible baseline for strong climbers, but most riders will be far happier with 34×34, which keeps cadence alive when the road rears toward its steepest ramps. If you can fit an even wider range, do it — spinning a light gear across 1718 m of gain preserves your legs for the thin air near the 2117 m summit. There is no glory in grinding a gear too big here.

Summary

Passo di Brealone earns its HC label honestly: 21.9 km, a 7.83% average, and a 21.9% maximum that adds up to 1718 m of net climbing from 399 m to 2117 m. Pace it to your threshold, gear it for the walls, and respect the altitude.

Length: 21.9 km
Average gradient: 7.83%
Max gradient: 21.9%
Start: 399 m
Summit: 2117 m
Net gain: 1718 m
Total ascent: 1692 m
Category: HC