Sur Cou

Overview

Sur Cou is a long, sustained category 1 climb that rewards patience over aggression. Over 16.5 km it lifts you from a valley floor at 411 m to a summit at 1367 m, a net gain of 956 m. The average gradient of 5.79% sounds moderate on paper, but 16.5 km is a serious stretch of road, and the total ascent of 973 m confirms there is no free rolling relief hidden inside it — nearly every metre of vertical is earned by pedalling.

This is the kind of climb where the clock, not the slope, does most of the damage. Settle in.

How the Gradient Unfolds

The headline number is 5.79%, but averages flatten the story. The difference between the net gain of 956 m and the total ascent of 973 m is only 17 m, which tells you this is an honest, one-directional climb — there are no significant descents or false valleys to recover on. Once you start going up, you keep going up.

What breaks the rhythm is the pitch. The maximum gradient hits 16.52%, nearly three times the average, so the climb is not uniform. Expect gentler stretches well below 5.79% that let you breathe, punctuated by sharp ramps that spike toward that 16.52% wall. Reading the road ahead matters: carry momentum into the steep sections rather than getting caught flat-footed.

Pacing Notes

On a climb this long, pacing is everything. The safest approach is to ride the whole 16.5 km just under your threshold and save matches for the steep ramps toward 16.52%. Your FTP is the number to anchor to here — hold a steady effort below it on the shallow sections, and allow short surges above it only where the gradient forces your hand.

If you do not know your threshold, estimate it before you ride with the FTP estimator. Knowing that figure turns Sur Cou from a guessing game into a controlled effort: you can budget how hard to push on the ramps and how much to hold back across the 956 m of climbing so you are not emptied out before the 1367 m summit.

Gearing

With ramps reaching 16.52% at the top of a 16.5 km climb, gear conservatively — running out of cassette on a steep pitch late in a long climb is miserable. A compact 34-tooth inner chainring is the sensible starting point.

Pair that 34 with at least a 32-tooth sprocket. A 34×32 will get most fit riders up the steady 5.79% sections comfortably and give a fighting chance on the steep ramps. If you climb at a lower cadence, carry extra weight, or simply want insurance for the 16.52% maximum, step up to a 34×34. That extra sprocket is cheap protection over 956 m of vertical, and you will be grateful for it near the summit.

Summary

Sur Cou is a long, steady category 1 climb defined by its length rather than any single wall — though the 16.52% ramps demand respect. Pace it below threshold, gear low, and let the numbers, not your ego, dictate the effort.

Length: 16.5 km
Average gradient: 5.79%
Max gradient: 16.52%
Start: 411 m
Summit: 1367 m
Net gain: 956 m
Total ascent: 973 m
Category: 1