Col d'Aussois cycling climb profile
Col d'Aussois is an HC climb in France that asks for patience before it asks for power. On paper, the headline is simple: 32.7 km at an average gradient of 6.66%, rising from 738 m to 2,914 m. In practice, those numbers point to a climb where the main risk is not one isolated hard section, but the accumulated cost of staying slightly too high for too long.
The 2,176 m net elevation gain is the defining feature. A climb of this length gives plenty of time for small pacing mistakes to compound, especially because the average gradient is already high enough to keep pressure on the pedals almost continuously. Treating it like a steady tempo climb from the bottom is tempting, but the listed maximum gradient of 31.04% is the warning sign: the profile is not simply a smooth 6.66% ramp to the summit.
How the gradient shapes the ride
With only the headline profile available, the safest reading is that Col d'Aussois combines a long aerobic demand with at least one extremely steep pitch. That matters because the average gradient hides the real tactical problem. If the climb averages 6.66% across 32.7 km but still reaches 31.04%, then some parts must be much more selective than the average suggests.
That changes how to ride it. The opening effort should feel controlled, not heroic. The climb is too long to spend early matches above sustainable climbing power just because the road feels manageable. The better strategy is to hold back enough that the steepest ramps can be absorbed without tipping into repeated surges well above /glossary/ftp.
Pacing and gearing notes
Pace the climb as a long endurance test with forced interruptions, not as a single steady-state effort. The average gradient gives you the baseline demand, while the maximum gradient tells you to prepare for low-cadence, high-torque moments.
Practical setup:
- Choose gearing for the 31.04% maximum gradient, not for the 6.66% average.
- Keep the first half deliberately conservative, because the 32.7 km length leaves little room to recover from overpacing.
- Avoid chasing speed on easier sections. Use them to bring breathing and cadence back under control.
- If riding by power, cap early surges and save above-threshold work for the steepest ramps.
- If unsure of your sustainable range, estimate it before the ride with /tools/ftp-estimator rather than guessing on the climb.
Bottom line
Col d'Aussois is hard because it combines scale and irregularity. The HC label fits: 32.7 km, 2,176 m of net gain, and a summit at 2,914 m make it a serious alpine-style effort even before accounting for the 31.04% maximum gradient. Ride it with restraint early, gear it generously, and respect the fact that the hardest moments may arrive after a long period of already-expensive climbing.