Col du Bonhomme

Overview

The Col du Bonhomme is a 9.1 km category 3 ascent that trades brute difficulty for rhythm. From a start elevation of 565 m it works its way up to a summit of 961 m, a net gain of 396 m. On paper the 4.37% average gradient reads as gentle, and for long stretches it genuinely is — but the total ascent of 589 m tells a more honest story than the net figure alone. That gap between 589 m climbed and 396 m gained means the road gives back elevation along the way, rolling and dipping rather than dragging you up a single unrelenting wall.

How the Gradient Unfolds

Do not let the 4.37% average lull you. A climb that averages under 5% but hides a 15.15% maximum is a climb of contrasts. The undulating profile — 589 m of total ascent for only 396 m of net gain — means you are constantly resetting your legs: a shallow drag, a brief respite, then a bite. The steepest pitch at 15.15% is more than three times the average, so the challenge here is not sustained suffering but the sharp, sudden efforts that punctuate an otherwise moderate 9.1 km. Riders who settle into a single steady gear will get caught out when the road tilts.

Pacing Notes

Because the effort is broken up, the smart approach is to pace off your threshold rather than off the gradient in front of you. Anchor your effort to your FTP and let the shallow sections be genuine recovery, spending your matches only on the steep ramps toward 15.15%. If you don't know your number, run a quick estimate with the FTP estimator before you ride — over 9.1 km, holding a touch under threshold on the flatter drags leaves headroom for the pitches without blowing up. Total ascent of 589 m over 9.1 km is very manageable when metered out; it only hurts if you burn matches early on gradients that don't warrant them.

Gearing

For a climb averaging 4.37% you don't need the deepest cassette on the market, but the 15.15% maximum changes the calculation. A compact 34-tooth chainring paired with a 34×32 will get most fit riders over the steep ramps at a workable cadence. If you tend to grind, or you're carrying fatigue into the 9.1 km, size up to a 34×34 — the extra sprocket costs nothing on the shallow sections and buys you spin when the road hits its steepest. Given only 396 m of net gain, either setup is defensible; choose based on how much you want to protect your legs on the sharp pitches.

Summary

The Col du Bonhomme is a deceptively rolling category 3 climb: mild on average, spiky in places, and best ridden with discipline. Meter your effort, respect the 15.15% ramps, and the 9.1 km passes smoothly.

Length: 9.1 km
Average gradient: 4.37%
Max gradient: 15.15%
Start: 565 m
Summit: 961 m
Net gain: 396 m
Total ascent: 589 m
Category: 3