Col de Cray

Overview

Col de Cray is one of those climbs that reads like a typo until you're actually on it. Over just 6.8 km it averages a savage 16.9%, and it doesn't relent so much as occasionally pause. From a start elevation of 815 m it drags you to a summit of 1959 m — a net elevation gain of 1144 m packed into a road barely longer than a warm-up. This is unmistakably hors catégorie (HC) terrain: the hardest tier, above category 1, 2, 3, and 4. There is no easing-in, no long false-flat approach to settle your legs. You simply point the bike uphill and start negotiating with gravity.

How the Gradient Unfolds

The defining number here is the average: 16.9% sustained across the whole 6.8 km. Most climbs earn their reputation from a few brutal ramps buried among gentler stretches, but Col de Cray inverts that logic — the whole thing is the brutal ramp. The maximum pitch hits 24.87%, and with an average this high, the "easier" sections are still steeper than the hardest parts of most alpine passes. Note the gap between net gain (1144 m) and total ascent (1066 m): the recorded total ascent is actually a touch lower than the net figure, which tells you this is an almost purely upward road with no meaningful dips or recovery descents to break the effort. What goes up, keeps going up.

Pacing Notes

On a climb this steep, pacing is less about ambition and more about survival. Your power will spike well above your sustainable threshold on the steepest ramps whether you like it or not, so the goal is to protect the sections you can control. Ride the shallower stretches conservatively so you have something left when the road tilts toward 24.87%. Know your FTP before you attempt this — anchoring your effort to a real threshold number is the difference between a steady grind and a mid-climb detonation. If you're unsure where yours sits, run the numbers through the FTP estimator first. At 16.9% average, even riders with strong thresholds will be deep in the red for extended stretches, so budget accordingly.

Gearing

Do not under-gear this climb. With a 16.9% average and pitches to 24.87%, a compact 34-tooth chainring paired with at least a 34×32 is the sensible floor, and most riders will be far happier with 34×34. If your frame and derailleur can accommodate an even larger cassette, take it — spinning a low gear at survivable cadence beats grinding a big gear until your knees or your will give out. On a road this steep, the difference between 34×32 and 34×34 is the difference between climbing and walking.

Summary

Col de Cray is short, steep, and uncompromising — a genuine HC test where the average gradient does the damage the length never gets a chance to. Come with low gears, a known threshold, and respect.

Length: 6.8 km
Average gradient: 16.9%
Max gradient: 24.87%
Start: 815 m
Summit: 1959 m
Net gain: 1144 m
Total ascent: 1066 m
Category: HC