Col d'Hérens cycling climb profile
Col d'Hérens is a Category 1 climb defined less by a savage average gradient and more by duration. At 49 km, with 1,752 m of net elevation gain from 653 m to 2,405 m, it asks a different question than a short wall or a classic high-gradient pass. The headline average of 3.57% can make it look manageable, but that number is spread across a very long climb and hides the practical reality: you are gaining height for a long time, and the steepest sections reach 12.07%.
That combination matters. A rider who treats the opening as free speed because the average looks modest can end up paying heavily later, especially once the road begins to bite. The total ascent is 1,760 m, which sits very close to the net elevation gain, so the climb is not defined by repeated descents or large interruptions. It is fundamentally a long upward effort.
How the gradient unfolds
With the available profile data, the safest way to read Col d'Hérens is as a sustained endurance climb with selective steep ramps rather than a consistently steep pass from bottom to top. The 3.57% average over 49 km tells you there must be significant gentler terrain mixed into the ascent. But the 12.07% maximum gradient is the number that should shape your gearing and pacing decisions, because those ramps are where a smooth aerobic ride can become a low-cadence grind.
The key is not to chase speed on the easier gradients. On a climb this long, the less demanding sections are where you preserve glycogen, keep cadence under control, and avoid turning the ride into a repeated series of accelerations. The steepest pitches should be absorbed, not attacked, unless the objective is a maximal effort.
Pacing and gearing notes
For a steady ride, pace Col d'Hérens from the bottom as if the real climb begins later than it appears to. That means riding comfortably below threshold early, staying smooth through the gentler gradients, and leaving enough margin for the 12.07% maximum sections. If you use power, anchor the effort to sustainable endurance or tempo rather than letting the low average gradient tempt you into riding by speed. For a refresher on why that matters, see /glossary/ftp.
Gearing should be chosen for the steepest ramps, not the average. A setup that feels efficient at 3.57% may become restrictive when the road kicks into double digits. The goal is to keep a seated cadence available when the gradient sharpens, because standing repeatedly across a 49 km ascent tends to turn a pacing problem into a muscular fatigue problem.
Col d'Hérens rewards patience. The riders who handle it best will be the ones who respect the total vertical gain, keep pressure on the pedals without forcing it, and save their harder efforts for the moments when the road actually demands them.