Col de Saint-Louis

Overview

Col de Saint-Louis is a Category 2 climb in France covering 5.3 km of road. Over that distance it delivers a net elevation gain of 348 m, rising from a start elevation of 345 m to a summit at 693 m. On paper it reads as a moderate, mid-length effort: short enough to attack, long enough to hurt if you get the pacing wrong.

The number that reshapes the effort is the total ascent of 472 m against that 348 m of net gain. The 124 m gap tells you the road does not climb cleanly. It undulates, giving back altitude in dips and false flats before clawing it straight back. That extra vertical is work you pay for without net reward, so the climb feels harder than a 348 m gain suggests. Treat the total ascent, not the net figure, as the real measure of the day.

How the Gradient Unfolds

The 6.55% average is a blend, not a description. With 124 m of re-climbing baked in, the profile hides both easier recovery stretches and pitches far steeper than the mean. The headline warning is the maximum gradient of 25.74% — a wall that no averaging can soften.

• Flatter and downhill sections that drag the average down and let you breathe
• Repeated short kicks where the road gives back altitude, then reclaims it
• A brutal ramp touching 25.74% that will spike your heart rate regardless of how you meter the rest

Pacing Notes

Because this climb undulates, even-speed pacing is a trap — holding a fixed speed forces huge power surges on the steep ramps and wasted effort on the descents. Pace to even effort instead. Anchor your target to a sustainable power output you can hold for the full 5.3 km, let your speed rise on the flatter sections, and accept a slower crawl on the 25.74% pitch rather than blowing your effort ceiling to defend a number.

If you do not know your ceiling, run the FTP estimator first and set a wattage cap you refuse to exceed except on the steepest wall.

Gearing

The 25.74% maximum dictates your setup, not the 6.55% average. A gradient that steep at the end of a Category 2 climb will overwhelm a standard chainset. Fit a compact or sub-compact crank and pair it with a wide-range cassette — a 34×32 at minimum, and a 34×34 if you want margin to keep spinning rather than grinding. Check your chainset and cassette before the ride, not at the base of the ramp, and confirm the rear derailleur clears your largest sprocket.

Summary

• Length: 5.3 km
• Average gradient: 6.55%
• Maximum gradient: 25.74%
• Net elevation gain: 348 m
• Total ascent: 472 m
• Category: 2

Col de Saint-Louis is a short climb with a long memory: 5.3 km that punishes anyone who reads the 6.55% average and ignores the 124 m of undulation and the 25.74% wall. Gear low, pace to effort, and it rewards you.