Col de Sorba

Overview

Col de Sorba is a Category 1 climb in France that earns its classification through sustained length and a gradient profile that keeps pressure on the legs from bottom to top. At 13.4 km with a net elevation gain of 869 m, the road rises from 440 m at the base to a summit of 1,309 m. The average gradient of 6.46% is honest — not extreme on paper, but over this distance it accumulates fatigue methodically.

The total ascent figure of 1,538 m against a net gain of 869 m tells an important story: there is meaningful undulation across the climb. The road does not give back much, but the gap between those two numbers confirms that gradient is not constant, and riders will encounter sections where the slope temporarily eases before tightening again.

Gradient Profile

The headline number is the maximum gradient of 22.79%. That is a severe ramp — the kind that demands either a very low gear or a high capacity to produce short, intense power above threshold. On a climb that averages 6.46%, a 22.79% spike represents a dramatic local steepening. Expect at least one section where the road kicks sharply and forces a gear change mid-effort.

Key gradient characteristics:

• Average gradient: 6.46% across 13.4 km
• Maximum gradient: 22.79% — treat this as a brief but serious obstacle
• Net elevation gain: 869 m
• Total ascent: 1,538 m — confirms irregular terrain throughout

The spread between average and maximum suggests the climb has pockets of relative relief interspersed with hard ramps. Riders who lock into a fixed pace based only on the average risk blowing up on the steeper pitches.

Pacing Notes

At 13.4 km this is not a short punch. Treat it as a sustained effort where managing FTP output across the full duration is more important than attacking early ramps. A common mistake on climbs with irregular gradients is going too hard through the first easier sections, then arriving at the steep ramps with depleted legs.

Recommended approach:

• Set a power or effort ceiling for the first half. The road will come to you.
• When the gradient softens below the average, do not accelerate — recover slightly and keep cadence steady.
• Identify the 22.79% ramp in advance if route data is available. If not, read the road: tightening hairpins and abrupt wall-like pitches are the tell. Drop to your lowest gear before you need it — shifting under maximum load risks a dropped chain or poor engagement.
• The final kilometres to 1,309 m will reflect whatever decisions were made in the first half. Budget accordingly.

Use the FTP Estimator to benchmark your sustainable power before planning a timed effort here.

Gearing

For most riders, a compact chainset (50/34) paired with an 11-32 or wider cassette is advisable. The 22.79% maximum pitch will push even strong climbers toward their easiest gear. If you are running a standard double, the 32+ cassette becomes essential rather than optional. Riders on 1x drivetrains should confirm their lowest gear ratio covers the steepest gradient before committing to a full effort.