Col du Bonhomme cycling climb profile
The Col du Bonhomme is an HC climb in France, and the numbers explain why before the road even starts: 25.6 km at an average gradient of 6.82%, rising from 581 m to 2,328 m. That gives it 1,747 m of net elevation gain, with 1,816 m of total ascent, so this is not a short test with a hard finish. It is a full-duration climbing effort where the main limiter is how well you manage the middle hour, not how fresh you feel at the base.
How the gradient unfolds
The average gradient is the defining feature. At 6.82%, the Col du Bonhomme sits in that awkward zone where it is never easy enough to truly recover, but not so steep that it forces an obviously defensive pace from the start. That makes it dangerous. The climb can tempt a rider into riding just above sustainable power because the slope feels manageable early, then slowly turn that mistake into a long fade.
The maximum gradient of 22.17% changes the pacing equation. Even if the climb averages below 7%, the steepest ramps are severe enough to create torque spikes and force a different cadence. Those sections should be treated as cost-control moments rather than places to prove form. If you surge hard over them, the price is paid later across the remaining vertical gain.
The gap between total ascent and net gain is small relative to the scale of the climb. Practically, that means any relief is limited. You should not plan around meaningful recovery sections. Plan around a long, mostly uphill load with occasional gradient changes that can disrupt rhythm.
Pacing strategy
The best approach is conservative early, controlled through the body of the climb, and only then opportunistic near the summit. On a climb this long, pacing by feel alone can be misleading because the first sustained gradients can feel comfortable while glycogen cost is already accumulating. If using power, anchor the effort around sustainable climbing intensity rather than chasing speed. If using heart rate, expect drift and avoid letting early enthusiasm push you above a level you can hold for the full 25.6 km. For reference, the idea of threshold pacing is covered in FTP.
A useful mental model is simple:
- First section: keep pressure smooth and avoid accelerations.
- Middle section: settle into the highest effort that still feels repeatable.
- Steep ramps: shift early, protect cadence, accept slower speed.
- Final section: only increase effort if breathing and legs are still under control.
Gearing notes
Bring climbing gears that let you stay seated through sustained gradients and still have a bailout option for the 22.17% maximum. A setup that feels fine on a steady 6.82% average may feel overgeared when the road pitches up sharply. The priority is cadence preservation. Grinding early on a climb with 1,747 m of net gain is usually a sign the gear is too big, not that the rider is being efficient.
The Col du Bonhomme rewards restraint. Ride the average gradient with respect, ride the steepest ramps without ego, and the climb becomes a long controlled effort rather than a slow unraveling.