Col de la Colombière

What Kind of Climb Is Col de la Colombière?

Col de la Colombière is a Category 1 Alpine climb that earns its classification honestly. Over 13.4 km, it delivers 1,001 metres of net elevation gain — from a start elevation of 624 m to a summit at 1,625 m — at an average gradient of 7.46%. That average sits firmly in the territory where under-fuelling or misjudging early pace compounds into a very long final kilometre.

The total ascent figure of 1,842 m is worth noting: it exceeds the net gain, which tells you the road isn't a clean straight ramp. There are gradient changes throughout, meaning the legs never settle into a single rhythm for long.

How the Gradient Unfolds

The 7.46% average is deceptive in the way most Alpine averages are. The recorded maximum gradient of 33.8% indicates at least one section that is, for most riders, effectively a forced dismount or an absolute limit-of-traction effort in the saddle. Treat that figure as a warning rather than a challenge to sprint.

The structure of the climb generally follows this pattern:

• Lower slopes: The opening kilometres from 624 m tend to be manageable — use this section to settle breathing and cadence, not to bank time.
• Middle section: Gradients stack. The road begins to demand more consistent output. This is where riders who went out too hard start to feel the cost.
• Upper slopes: With the summit at 1,625 m, the final kilometres are exposed and frequently windier. Gradient spikes in this zone, combined with altitude and accumulated fatigue, are where races — and personal efforts — are decided.

Pacing Notes

At 13.4 km and 7.46% average, this is not a climb to attack from the base. Target a power output you can sustain for the full duration — typically in the range of 90–95% of your threshold for a well-trained rider, lower if the day includes significant climbing before Colombière. See how to estimate your FTP if you're unsure of your baseline.

Key pacing principles for this climb:

• Do not chase the maximum. The 33.8% pitch will arrive without much warning. Soft-pedalling into it wastes less energy than braking out of an unsustainable sprint.
• Use VAM as your guide. On a climb this long, tracking vertical metres per hour gives you a more honest picture of sustainable effort than speed, which fluctuates with gradient. See the VAM glossary entry.
• Cadence flexibility matters. A climb with gradient swings this wide requires gearing that lets you spin through steep ramps without grinding. A compact or sub-compact chainring paired with a wide-range cassette is not a luxury here — it is functional equipment.
• Wind exposure increases near the top. Factor this into your perceived effort. A headwind on the upper slopes can add significant wattage demand without any change in gradient.

Gearing Recommendation

Given a maximum gradient of 33.8% and a summit at 1,625 m after 13.4 km of cumulative load, riders should arrive with a low gear in the 34×32 range at minimum. Anyone running a standard 53/39 chainring without a wide cassette will be in trouble on the steepest pitch. If your bike setup doesn't already account for long Alpine climbs, review your options before arriving at the base.

For context on how gear selection interacts with sustainable power on steep gradients, see the FTP and pacing guide.