Col Cornet

Overview

Col Cornet is an hors catégorie climb, the hardest rating in cycling, and its numbers explain why. Over 19.8 km the road lifts you from a start elevation of 586 m to a summit at 2053 m. That is a net elevation gain of 1467 m, delivered at an average gradient of 7.39%. There is no gentle build-up hiding in those figures: nearly 20 kilometres held at close to seven and a half percent is the kind of effort that rewards patience and punishes ambition. This is a climb you ride with your head as much as your legs, settling into a rhythm early and defending it all the way to the top.

How the Gradient Unfolds

The headline average of 7.39% tells you the sustained nature of the challenge, but the shape matters too. With a net gain of 1467 m and a total ascent of 1435 m, almost every metre you climb is metres you keep — there is very little false-flat or descending relief to break the effort. That difference of 32 m between net gain and total ascent is tiny across 19.8 km, which confirms the road climbs almost continuously. Expect long, honest ramps that hover around and above the average rather than sharp spikes followed by recovery. On a climb like this, the danger is not a single brutal wall but the accumulated cost of holding 7.39% for well over an hour.

Pacing Notes

Discipline is everything on Col Cornet. Because the gradient sits close to its 7.39% average for the full 19.8 km, small surges early carry a large price later. Anchor your effort to a percentage of your FTP and hold it steadily — most riders will want to sit just below threshold for a climb of this length, leaving a margin for the upper slopes near 2053 m where thinner air quietly saps power. If you are unsure of your number, run the FTP estimator before you commit to a target. Break the 19.8 km into segments in your head and tick them off; a climb of 1467 m of gain is far more manageable as a series of shorter goals than as one intimidating whole.

Gearing

An HC climb of this length demands generous gearing. For most riders a compact 34-tooth inner chainring paired with a wide cassette is the right foundation. A 34×32 will get many trained cyclists up Col Cornet, but on a climb averaging 7.39% for 19.8 km, the extra range of a 34×34 buys you a lower spin and protects your legs on the sustained upper slopes. If your setup allows even more range, take it — nobody regrets an easier gear near 2053 m. The goal is to keep cadence up and torque down so you arrive at the summit with something left.

Summary

Col Cornet is a true test of endurance: long, steady, and unforgiving from 586 m to 2053 m. Pace it with respect, gear it generously, and it becomes one of the most satisfying HC efforts you can log.

Length: 19.8 km
Average gradient: 7.39%
Max gradient: n/a
Start: 586 m
Summit: 2053 m
Net gain: 1467 m
Total ascent: 1435 m
Category: HC