Col de Marignac

Overview

Col de Marignac is a Category 3 climb in France, rising over 12.3 km from a start elevation of 354 m to a summit at 747 m. On paper it is a modest ascent: 393 m of net elevation gain spread across more than twelve kilometres, which averages out to a gradient that most riders would call comfortable. The category and the length together suggest a long, steady drag rather than a wall.

But the numbers hide something. The net elevation gain is 393 m, while the total ascent is 544 m — a 151 m gap. That difference is climbing you do twice, because the road dips and rises repeatedly instead of trending cleanly upward. You pay for those 151 m of extra vertical without them showing up in the summit figure. Expect an undulating profile where the effort is lumpier than the average implies.

How the Gradient Unfolds

The 3.19% average gradient is a poor guide to how this climb actually feels. Averages flatten out the very sections that decide your ride: the recovery dips that let you soft-pedal, and the short ramps where the road kicks up hard. The steepest pitch here hits 11.21%, roughly three and a half times the average — a gradient you cannot spin through casually.

• Flatter and downhill recovery sections where the road gives back elevation, keeping the average low
• Repeated short climbs that stack up to the 544 m total ascent rather than a single sustained gradient
• A steepest ramp of 11.21%, well above anything the average prepares you for

Pacing Notes

On an undulating climb like this, even-speed pacing will wreck you. Chasing a constant speed forces you to surge on every one of those short ramps and coast through the dips, spiking your effort exactly where it hurts most. Pace by effort instead. Hold a steady sustainable power output through the steep pitches, let your speed rise naturally on the flatter and downhill sections, and never bury yourself trying to hold a number on the 11.21% ramp. If you do not know your ceiling, run the FTP estimator before you go, then ride the steep bits just under it.

Gearing

The 11.21% maximum is what dictates your setup, not the gentle average. A compact (50/34) or sub-compact chainset paired with a wide-range cassette — 34×32 or 34×34 — gives you the low gear to keep cadence up over the steepest ramp without grinding. If you are geared for the 3.19% average, that ramp will force you out of the saddle and into the red. Check your chainset and cassette before the ride; swapping a cassette is a five-minute job at home and impossible on the climb.

Summary

• Length: 12.3 km
• Average gradient: 3.19%
• Maximum gradient: 11.21%
• Net elevation gain: 393 m
• Total ascent: 544 m
• Category: 3

Treat Col de Marignac as a rhythm climb with teeth. The category and average say easy, but the 151 m of extra ascent and the 11.21% ramp reward riders who pace by effort and carry a low enough gear to stay smooth.