Passo San Marco

Overview

Passo San Marco is a full-blooded HC climb: 22 km of continuous ascent that lifts you from 269 m at the base to 1984 m at the summit. That is a net gain of 1715 m, with a total ascent of 1708 m once you account for the handful of shallow pitches that briefly ease the strain. At an average gradient of 7.8%, this is not a climb you can bluff your way up. It sits in the hardest category on the road — hors catégorie — and it earns the label through sheer, sustained length rather than a single wall.

How the Gradient Unfolds

The headline number, 7.8% average over 22 km, tells only half the story. Because that figure is a mean, long stretches sit well above it, and the maximum pitch reaches 16.99% — more than double the average. Expect the climb to breathe in and out: sections that hover near or above 10% are balanced by brief lulls that let the total ascent (1708 m) fall just short of the raw net gain (1715 m). Practically, that means you rarely get true recovery. The shape rewards riders who can hold a steady, honest effort for well over an hour rather than those who surge and fade.

Pacing Notes

On a climb this long, discipline beats ambition. Anchor your effort to your FTP and resist the temptation to chase the early ramps. A sensible target for a full 22 km ascent is a sub-threshold pace you can defend to the summit, with the 16.99% pitches ridden at controlled power rather than a heroic spike. If you are unsure where your threshold sits, run the numbers through the FTP estimator before you commit. Fuel and drink from the bottom, because 1715 m of vertical is a long time in the red if you start too hot.

Gearing

Gear for the steepest ramps, not the average. With a maximum of 16.99% arriving after you may already have thousands of feet in your legs, you want more range than a standard road setup offers. A 34×32 is the sensible minimum for most riders tackling an HC climb of this length, and if you climb at a lower cadence or carry any extra load, step up to a 34×34. The extra sprocket costs you nothing on the flat and buys you a spinnable gear when the road tilts toward 17% — exactly where a cross-chained slog can end a good ride.

Summary

Passo San Marco is a classic hors catégorie test: long, relentless, and unforgiving of a bad pacing plan. Ride within yourself early, gear generously, and let the 22 km come to you.

Length: 22 km
Average gradient: 7.8%
Max gradient: 16.99%
Start: 269 m
Summit: 1984 m
Net gain: 1715 m
Total ascent: 1708 m
Category: HC