Col de Pierre Joseph

Overview

The Col de Pierre Joseph is a hors catégorie monster measured in patience as much as watts. At 33.7 km long, it is a climb you settle into rather than attack, rising from a start elevation of 612 m all the way to a 2478 m summit. That gives a net elevation gain of 1866 m, with a total ascent of 1830 m once you account for the handful of shallow dips along the way. The average gradient of 5.53% sounds friendly on paper, but over this distance it adds up relentlessly, and a max gradient of 13.65% guarantees the road bares its teeth more than once.

How the Gradient Unfolds

The headline 5.53% average is a smoothing average, not the lived experience. Because the difference between the 1866 m of net gain and the 1830 m of total ascent is small, false-flats and descents are minimal here — the road almost always points up. What varies is intensity. Long stretches sit near or just above the average, letting you find a rhythm, before the gradient ramps toward that 13.65% ceiling on the steepest ramps. Above roughly the midpoint, thinning air near a 2478 m summit quietly steepens the effort even when the numbers hold steady. Expect the last third to feel harder than its raw percentage.

Pacing Notes

On a climb this long, discipline beats bravado. Anchor your effort to a percentage of FTP rather than to how you feel in the first kilometres — the 33.7 km will punish anyone who starts hot. A sustainable target for most riders is a shade below threshold, leaving headroom to absorb the 13.65% ramps without redlining. If you are unsure of your number, run it through the FTP estimator before you commit to a pace. Meter your fuelling across the full ascent; with 1866 m to gain, this is an eat-early, eat-often effort.

Gearing

Gear for the summit, not the lower slopes. With a 13.65% max gradient arriving deep into a 33.7 km climb, tired legs need bail-out ratios. A compact 34-tooth chainring paired with a wide cassette is the sensible baseline: 34×32 will carry strong climbers through most of the steep sections, but for the majority of riders — especially anyone loaded or arriving fatigued — 34×34 gives the extra cadence room that keeps the effort aerobic rather than muscular. On an HC ascent, spinning a lower gear almost always beats grinding a bigger one.

Summary

The Col de Pierre Joseph rewards riders who respect its length. Pace to your threshold, gear low enough to spin the 13.65% ramps, and treat the full 1866 m of climbing as one long, controlled effort to the 2478 m summit.

Length: 33.7 km
Average gradient: 5.53%
Max gradient: 13.65%
Start: 612 m
Summit: 2478 m
Net gain: 1866 m
Total ascent: 1830 m
Category: HC