Col de Nannaz cycling climb profile
The Col de Nannaz is an HC climb in Italy, and the category is justified less by one isolated feature than by the total load it places on the rider. At 32.4 km, with 2,211 m of net elevation gain from 436 m to 2,647 m, this is a climb where pacing matters more than aggression.
The headline average of 6.82 percent is the key number, but it needs to be read correctly. On a short climb, that gradient can be ridden above threshold and survived. Over this distance, it becomes a long aerobic constraint. If the effort drifts too high early, the cost compounds for a very long time.
How the gradient unfolds
The available profile numbers point to a sustained climb with a hard ceiling rather than a climb defined by a single short sting. The average gradient is already significant, and the maximum gradient reaches 15.47 percent, which means the road can bite hard even if the overall climb is more about duration than repeated walls.
Without detailed kilometre-by-kilometre splits, the safest way to read the ascent is this: expect the baseline to sit around a steady climbing effort, then plan for steeper ramps that force cadence down and torque up. Those ramps are where riders who have been riding the average too close to their limit can unravel.
The altitude gain also changes the character of the climb. Starting at 436 m and finishing at 2,647 m means the final portion comes after a large vertical accumulation. Even if the gradient does not become objectively harder near the top, it will feel harder because the legs have already absorbed more than two thousand metres of climbing.
Pacing strategy
Ride the first part with restraint. For a climb of this length, the correct opening effort should feel almost too controlled. Use /glossary/ftp as the anchor if riding with power, but avoid treating the early kilometres like a test. The goal is to arrive deep into the climb still able to respond to the 15.47 percent sections without spiking repeatedly.
A good rule for this profile is to separate effort from speed. On a 32.4 km climb, speed will naturally fluctuate with gradient changes, but the physiological cost should remain controlled. Let the steep ramps slow the bike rather than forcing a high-power surge to preserve momentum.
Gearing notes
Bring low gears. The 6.82 percent average is manageable with standard climbing gearing for strong riders, but the 15.47 percent maximum makes bailout range valuable. Compact or sub-compact gearing paired with a wide cassette is the practical choice for most riders, especially if the climb comes after other work.
Cadence preservation matters here. Grinding early on a climb with 2,211 m of net gain is a tactical mistake because it loads the muscles before the longest part of the effort has played out. Choose gearing that lets the steepest pitches be ridden under control, not survived through force.
Bottom line
The Col de Nannaz is not a climb to bluff. Its difficulty comes from the combination of HC length, sustained average gradient, and sharp maximum pitch. Pace it like an endurance climb, gear it for the steepest ramps, and save the real commitment for the upper half rather than the opening kilometres.