Col de la Croix de Fer

Col de la Croix de Fer cycling climb profile

The Col de la Croix de Fer is a big, sustained HC climb in France: 22.8 km from a start elevation of 445 m to a summit elevation of 1975 m, with 1530 m of net elevation gain and 1535 m of total ascent. The average gradient is 6.71%, but the headline number that should shape your pacing plan is the maximum gradient of 17.56%.

That combination tells you almost everything important about how this climb rides. It is long enough that any early overreach will compound, and it is steep enough in places that riding purely by feel can become expensive very quickly. The total ascent is only slightly higher than the net gain, which suggests the climb is primarily an upward effort rather than a route broken up by meaningful descending. In practical terms, you should expect a long accumulation of load with very little opportunity to fully reset.

How the gradient unfolds

With a 6.71% average across 22.8 km, the Col de la Croix de Fer is not defined by a single short wall. It is defined by duration. The average is demanding but manageable if ridden under control, while the 17.56% maximum gradient shows that the climb includes much sharper ramps that can force a change in cadence, gearing, and effort.

Because the available data does not place those ramps on the climb, the safest assumption is tactical rather than geographic: save enough margin to handle steep sections whenever they arrive. A rider who treats the average gradient as the whole story will likely be overgeared or over-threshold when the hardest gradients appear.

Pacing and gearing notes

The right strategy is restraint early, discipline through the middle, and only a controlled lift once the summit is realistically close. For most riders, this is a climb to ride below hard-threshold sensations for a long time, using /glossary/ftp as an anchor rather than chasing speed. The gradient and length reward even power more than surges.

Gearing should be chosen for the steepest ramps, not the average gradient. A setup that feels comfortable at 6.71% may become a liability when the road pitches toward 17.56%. Prioritize a low enough climbing gear to keep cadence alive when the slope bites, because grinding too early on a 22.8 km HC ascent is exactly how the final part of the climb becomes damage control.

If riding it in a sportive, training block, or as part of a bigger mountain day, the key is to respect the full 1530 m of net gain. Fuel before you feel behind, keep the first sustained effort contained, and avoid matching every change in gradient with a change in intensity. The climb is hard because it stacks length, elevation gain, and steep ramps into one continuous problem.