Les Portes d'Oche

Overview

Les Portes d'Oche is a hors catégorie ascent that earns every letter of its rating. Over 22.5 km the road drags you from a valley floor at 392 m up to a summit at 1970 m — a net gain of 1578 m at an average gradient of 7.02%. That average is honest but deceptive: a climb this long almost never holds a steady grade, and the 28.74% maximum tucked somewhere along the way tells you the road has teeth. With a total ascent of 1619 m — slightly more than the net figure once brief dips are counted — this is a full day's centerpiece, not a warm-up.

How the Gradient Unfolds

Think of the 7.02% average as a budget spread unevenly across 22.5 km. Long HC climbs typically stack their punishment in bursts, and the presence of a 28.74% pitch means at least one section is more than four times steeper than the average. Where the road eases toward false-flat, you bank effort; where it rears up toward that maximum, you spend it. The gap between the 1578 m net gain and the 1619 m total ascent — 41 m — signals rolling relief on the way up, small descents or flats that break the relentless upward pull but also cost you rhythm each time the climbing resumes. Treat every steep ramp as its own problem to solve rather than trying to average the whole mountain in your head.

Pacing Notes

On a climb of this length, discipline beats bravado. Your target effort should sit near or just below your sustainable threshold — anchor it to your FTP so you have a concrete number to hold rather than riding on feel alone. If you don't have a current figure, run it through the FTP estimator before you start planning splits. The danger on a 22.5 km climb averaging 7.02% is spending too early: the 28.74% ramp will punish anyone already in the red. Ride the shallower sections steady, allow your power to spike only briefly on the steepest pitches, and let it settle again the moment the grade relents. With 1578 m to gain, consistency over the full hour-plus is what gets you to 1970 m intact.

Gearing

Gear for the maximum, not the average. A 28.74% pitch on tired legs demands a bailout ratio, so a compact 34-tooth chainring paired with a wide cassette is the sensible baseline. A 34×32 will get most fit riders up the sustained 7.02% sections, but for the steepest ramps — and for the back half of a 1619 m total ascent — a 34×34 gives you the extra margin to keep spinning instead of grinding. If your setup allows an even larger sprocket, take it; on a climb this long, cadence preservation is what protects your legs across all 22.5 km.

Summary

Les Portes d'Oche is a proper HC test: long, steep in bursts, and unforgiving if you misjudge your effort. Respect the 28.74% max, gear conservatively, and pace to your threshold, and the 1970 m summit is well within reach.

Length: 22.5 km
Average gradient: 7.02%
Max gradient: 28.74%
Start: 392 m
Summit: 1970 m
Net gain: 1578 m
Total ascent: 1619 m
Category: HC