Col de Bigorno

Overview

Col de Bigorno is a Category 1 climb in Corsica, starting at 143 m elevation and finishing at a summit of 891 m. The road covers 11.4 km and delivers 748 m of net elevation gain, but the total ascent figure of 1,239 m tells a more important story: the road undulates enough that you earn considerably more vertical than the start-to-finish differential suggests. That gap — nearly 500 m of extra climbing baked into the middle of the route — means energy management is not optional here.

Gradient Profile

The average gradient of 6.56% is deceptive. On paper it sounds manageable for a Category 1 climb. In practice, a maximum gradient of 29.48% confirms that the road spikes sharply and repeatedly. Sections at that kind of ramp rate are not sustained — no road averages 6.56% while hitting 29.48% at a single point unless the terrain is doing a lot of swinging — but knowing the spikes exist should shape your approach from the bottom.

Expect the lower slopes to lull you. The early kilometres out of the valley floor around 143 m tend to feel controlled, and the temptation is to bank speed or simply ride by feel. Resist. The total ascent figure of 1,239 m versus the 748 m net gain means there are genuine descents or flat recoveries embedded in the route, and those transitions — from descent back into a steep ramp — are where riders get caught out if they have already spent their matches.

Key Gradient Zones

• Lower third: Gradient builds gradually from the start. Use this to settle breathing and establish a sustainable power output relative to your FTP.
• Mid-climb ramps: The maximum gradient of 29.48% almost certainly lives in the mid-to-upper section. Anticipate short, brutal kicks that require either a gear change in advance or a willingness to go briefly into the red and recover.
• Upper kilometres: With 891 m as the summit, the final approach climbs well above the tree-line terrain typical of this elevation band. Wind exposure can increase, and fatigue compounds any gradient steeper than 10%.

Pacing Notes

For a climb of this length and character, even pacing by power is the baseline strategy. Given the variable gradient, a normalized power approach will serve you better than trying to hold a fixed watt target. You can use the FTP estimator to set your ceiling before you start.

• Do not attack early ramps. The total ascent surplus over net gain tells you the road gives back elevation mid-climb. Use those recovery sections to bring heart rate and respiration down rather than pushing through them.
• Pre-shift before the steep ramps. A 29.48% gradient requires your smallest gear combination. Be in that gear before the pitch steepens — trying to shift under full load on a 20%+ ramp risks a dropped chain or a stall.
• Cadence strategy: On the extreme ramps, maintaining even 60–65 rpm in your lowest gear is a realistic target. A forced slow cadence at high torque is still more survivable than spinning out from the wrong gear choice.

Gearing Recommendations

This is not a climb to attempt on a standard road double chainring without a wide-range cassette. A compact crankset (50/34) paired with at least an 11-32 or 11-34 cassette is the minimum sensible setup. Riders on a 1x drivetrain should verify they carry enough range at the low end — a 29.48% gradient at any meaningful road speed is demanding regardless of fitness level.

For broader context on how to categorize and approach climbs like this, see the climb categories guide.

Bottom Line

Col de Bigorno is a genuine Category 1 effort. The 6.56% average flatters what is a technically aggressive road. The 29.48% maximum gradient and the near-500 m surplus in total ascent over net gain confirm that this climb punishes anyone who treats it as a steady sufferfest rather than a dynamic, variable challenge. Ride it with a plan, carry the right gearing, and save something for the ramps that the average gradient does not warn you about.