Antronapass

Overview

Antronapass is a hors-catégorie climb that trades brute steepness for sheer, unrelenting length. Over 28.3 km it averages 5.4%, lifting you from a start elevation of 701 m to a summit at 2229 m. That is a net gain of 1528 m with 1509 m of total ascent — numbers that put it firmly in HC territory, the hardest category before you run out of labels entirely.

The headline figure is that length. At nearly 28.3 km, this is not a climb you attack; it is a climb you manage. The 5.4% average is deceptively civil, but with a maximum pitch of 14.74% lurking somewhere in the profile, the effort is far from constant. Expect long stretches around the average punctuated by ramps that force you out of rhythm.

How the Gradient Unfolds

A 5.4% average across 28.3 km means the road rarely gives you flat recovery, but it also rarely pins you to the limit for long. The tell-tale sign of this climb is the gap between the 5.4% average and the 14.74% maximum: that near-nine-point spread means the gradient swings hard around its mean.

Because total ascent (1509 m) sits just below net gain (1528 m), there is almost no descending mixed in — this is a climb that goes up, stays up, and keeps going up. Plan for the steepest sections to feel disproportionately punishing precisely because they arrive after so much accumulated fatigue. A 14.74% ramp early is a nuisance; the same ramp at 20 km is a different animal entirely.

Pacing Notes

On a climb this long, pacing is everything. The single biggest mistake is treating the gentle 5.4% average as an invitation to push — 28.3 km will find you out. Anchor your effort to your sustainable threshold rather than to how fresh you feel in the first hour.

Ride the bulk of the climb just below your FTP, leaving headroom for the 14.74% maximum pitches where power naturally spikes. If you do not know your threshold, run the numbers first with the FTP estimator so you set a target watt figure you can actually hold for the full ascent. Meter your effort evenly across all 1528 m of gain; the summit at 2229 m is a long way from the 701 m start, and negative-splitting a climb of this scale beats fading in the final third.

Gearing

Gear for the length, not the average. A compact setup pairing a 34-tooth inner ring with a wide cassette is the sensible baseline here. On the shallower stretches near 5.4% a 34×32 will spin comfortably, but the 14.74% maximum — especially deep into the 28.3 km — is where you will be grateful for more range.

If your legs or your loading suggest a hard day, fit a 34×34 and give yourself the extra bailout gear. Preserving cadence over 1528 m of climbing matters more than the small weight penalty of a bigger sprocket.

Summary

Antronapass is a patience climb: a 28.3 km HC effort where the modest 5.4% average masks 1528 m of vertical and pitches up to 14.74%. Pace it conservatively, gear it generously, and let the summit come to you.

Length: 28.3 km
Average gradient: 5.4%
Max gradient: 14.74%
Start: 701 m
Summit: 2229 m
Net gain: 1528 m
Total ascent: 1509 m
Category: HC