Croix de Javerne

Overview

Croix de Javerne is one of the most savage climbs you can point a road bike at. Over just 8.4 km it averages a staggering 17.99%, and there is nothing forgiving hiding inside that number. It carries the HC label — hors catégorie, the hardest classification, sitting above categories 1 through 4 — and it earns it without argument. You start at 422 m and finish at 1927 m, a summit that puts you deep into high-alpine air. The net elevation gain is 1505 m, with 1480 m of total ascent, meaning almost every metre you climb stays climbed. This is not a rolling road with a hard finish; it is a sustained near-vertical effort from bottom to top.

How the Gradient Unfolds

The defining feature of Croix de Javerne is its relentlessness. An average of 17.99% over 8.4 km is the kind of figure that most riders associate with short, brutal ramps — not an eight-kilometre climb. Because the net gain (1505 m) is close to the total ascent (1480 m), there are essentially no descents or flat recovery stretches to break the effort. The road simply keeps tilting upward. On a climb like this the "shape" is less a profile with distinct sections and more a single, unbroken wall. Expect the gradient to sit far above what your legs consider sustainable, and to stay there. There is no rhythm to settle into other than the rhythm of survival.

Pacing Notes

At this gradient, pacing is everything — go too hard in the opening kilometre and the remaining distance to 1927 m will end you. Ride to power, not feel. Your FTP is the number that matters here, because sustaining even a modest percentage of it for the full 8.4 km at 17.99% is a genuine test. If you do not have a recent figure, run the numbers through the FTP estimator before you commit to a target. Aim to hold a steady effort just below threshold from the base at 422 m, and accept that on the steepest pitches your speed will drop dramatically even at full FTP output. Patience is not optional; it is the only way to reach the top.

Gearing

Do not underestimate what 17.99% over 8.4 km demands. A compact chainring paired with a wide-range cassette is the minimum sensible setup. A 34×32 will get many strong riders up, but on a climb this steep it leaves almost no margin — you will be grinding at low cadence for a long time. For most riders a 34×34 is the smarter choice, buying you the extra low gear that keeps your knees and your morale intact when the road refuses to relent. If your bike accepts something even easier, use it. There is no shame in spinning up a wall that gains 1505 m.

Summary

Croix de Javerne is a pure HC monster: 8.4 km of near-relentless climbing at 17.99%, lifting you 1505 m from valley to alpine summit. Respect the gradient, gear low, and pace with discipline.

Length: 8.4 km
Average gradient: 17.99%
Max gradient: n/a
Start: 422 m
Summit: 1927 m
Net gain: 1505 m
Total ascent: 1480 m
Category: HC