Col du Luissel

Overview

The Col du Luissel is a hors catégorie climb, the hardest rung on the classification ladder above categories 1 through 4. Over 14.7 km it lifts you from a valley floor at 378 m to a summit at 1640 m, a net elevation gain of 1262 m. The total ascent tallies 1235 m, meaning almost every metre of the road tilts upward — there is very little false flat or recovery hidden inside this profile.

At an average gradient of 8.59%, Luissel sits firmly in the range where an HC label is earned rather than given. The number that defines it, though, is the max gradient of 39.92%, a wall steep enough to force many riders out of the saddle and, on the very worst pitches, off the bike entirely.

How the Gradient Unfolds

Averages flatten the truth. An 8.59% mean across 14.7 km already promises a relentless grind, but the gap between that figure and the 39.92% maximum tells you the climb is not evenly graded. Somewhere on this road the pitch is more than four and a half times steeper than the average, and that spike dictates how you ride everything around it.

With 1235 m of total ascent packed into 14.7 km and a net gain of 1262 m, there is effectively no downhill to reset your legs — the small difference between net gain and total ascent shows how little the road gives back. Expect the gradient to swing hard: stretches near the average that let you settle into a rhythm, punctuated by ramps that stab toward that 39.92% figure and blow any rhythm apart. The mental game is refusing to let those spikes convince you the whole climb feels that way.

Pacing Notes

On a climb this long and this steep, pacing is survival. Anchor your effort to your FTP and hold something in reserve for the ramps — the 8.59% average is your baseline, but the pitches toward 39.92% will spike your power far above threshold whether you like it or not. Ride the shallow sections a touch below your ceiling so those surges do not bury you.

If you are unsure where your threshold sits, run the numbers through the FTP estimator before you commit to a target. With 1262 m of climbing to absorb, going out too hard in the first few kilometres is the classic mistake here.

Gearing

Gear for the wall, not the average. An 8.59% mean over 14.7 km is demanding on its own, but the 39.92% max is what determines your smallest cog. A compact 34-tooth chainring paired with a 34×32 is the minimum most riders should consider on an HC climb like this. Given the severity of the steepest ramps and 1235 m of total ascent, a 34×34 is the smarter choice — the extra range keeps your cadence alive when the road pitches toward its maximum. If your bike can take an even wider cassette, take it; you will never regret spinning up a 39.92% ramp instead of grinding it.

Summary

Col du Luissel is a genuine test: 14.7 km of near-continuous climbing at 8.59%, topping out at 1640 m after 1262 m of net gain, with a max pitch of 39.92% that earns its hors catégorie billing. Pace it against your threshold, gear low, and respect the ramps.

Length: 14.7 km
Average gradient: 8.59%
Max gradient: 39.92%
Start: 378 m
Summit: 1640 m
Net gain: 1262 m
Total ascent: 1235 m
Category: HC