Coll de la Dona Morta

Overview

The Coll de la Dona Morta is a hors catégorie climb that earns its HC rating the honest way — with length and gradient that never let up. Over 12.8 km the road lifts you from 230 m at the base to a summit of 1310 m, a net elevation gain of 1080 m. The average gradient reads 8.45%, and unlike gentler HC climbs that hide easy stretches behind an inflated headline number, this one holds close to that figure for most of its length. The steepest pitch bites at 20.53%, more than double the average, so even riders comfortable at threshold will find moments that demand a hard reset of rhythm and cadence.

How the Gradient Unfolds

An 8.45% average across 12.8 km means there is almost nowhere to recover. The total ascent of 1028 m sits just below the net gain of 1080 m, a 52 m difference that tells you the road climbs almost continuously with only the faintest dips — there are no descents to coast through and reset your legs. The defining feature is the spike to 20.53%. A pitch that steep against a backdrop already near 8.45% is where races are decided and where an under-geared rider is forced out of the saddle whether they like it or not. Treat the climb as one sustained effort punctuated by that single savage ramp, rather than a series of distinct sections.

Pacing Notes

On a climb this long and this steep, pacing is everything. Anchor your effort to your FTP rather than to feel — an 8.45% average will pull you above threshold within minutes if you let the early slopes dictate the pace. Aim to sit just under threshold for the bulk of the 12.8 km, holding something in reserve for the 20.53% ramp, where power will briefly spike no matter how disciplined you are. If you don't know your current threshold, run the numbers through the FTP estimator before you commit to a target. Banking 1080 m of climbing is a long time in the saddle; the riders who finish strongest are the ones who resist the temptation to spend early.

Gearing

Gear for the 20.53% pitch, not the 8.45% average — the average is what you'll ride, but the max is what will hurt you. A compact 34-tooth chainring paired with a wide cassette is the sensible baseline here. A 34×32 will get most fit riders up the sustained slopes, but on a 12.8 km HC climb with a ramp past 20%, the extra relief of a 34×34 is well worth carrying. That single-tooth difference at the low end preserves cadence and spares your knees over 1080 m of gain. If your bike allows an even larger sprocket, don't hesitate on a climb of this severity.

Summary

The Coll de la Dona Morta is a pure HC endurance test: long, steep, and unrelenting from 230 m to 1310 m. Pace it off your threshold, gear low enough for the 20.53% wall, and respect the sheer volume of climbing.

Length: 12.8 km
Average gradient: 8.45%
Max gradient: 20.53%
Start: 230 m
Summit: 1310 m
Net gain: 1080 m
Total ascent: 1028 m
Category: HC