Coll dels Terrers

Overview

Coll dels Terrers is a hors catégorie climb that earns its HC rating without ambiguity. Over 10.1 km the road lifts from 100 m at its base to a 1159 m summit, an average gradient of 10.49% that almost never relents. That is 1059 m of net vertical gain, with 1014 m of total ascent packed into the ride up — a sign that once you start climbing here, you stay climbing. There is no soft warm-up, no valley of recovery. From the first pedal stroke this is a sustained double-digit effort, and the 19.31% maximum gradient tells you the road has teeth.

How the Gradient Unfolds

The defining trait of Coll dels Terrers is relentlessness. An average of 10.49% across a full 10.1 km means there is very little coasting and very few flat sections to hide the true difficulty. Because the average sits so close to the maximum in character, the climb never gives back what it takes. The 19.31% pitch is the sharpest moment — a wall roughly 8.82 percentage points above the average — and ramps like that are where riders blow up if they arrived at the base already deep in the red. Between those spikes, expect long stretches hovering around and above 10%, the kind of steady, grinding gradient that quietly drains the legs kilometre after kilometre. With 1059 m of climbing to gain from 100 m to 1159 m, the mountain simply keeps stacking elevation the entire way.

Pacing Notes

On a climb this long and this steep, pacing is everything. Riding it well means holding a controlled, sustainable power from the bottom rather than chasing the early ramps. A useful anchor is your FTP: on an HC effort of this length, most riders climb best sitting just below or right around threshold, leaving headroom for the 19.31% surges without going anaerobic and cracking. If you do not know your threshold number, run the numbers through the FTP estimator first, then set a target that you can defend for the full 10.1 km. The steepest pitch will spike your power well over target for short bursts — accept that, but recover your rhythm immediately afterward. Average 10.49% for over ten kilometres and any pacing error compounds quickly.

Gearing

Gear for survival, not ego. With a 10.49% average and a 19.31% maximum, you want the easiest ratio your bike allows. A compact 34-tooth chainring paired with a wide cassette is the sensible baseline: 34×32 gives you a workable low gear for the sustained sections, but on a climb that touches 19.31% many riders will be glad of 34×34 to keep the cadence up and the knees happy on the walls. If your frame accepts an even larger sprocket, take it — spinning a low gear beats grinding to a halt on a HC ascent.

Summary

Coll dels Terrers is a pure test: long, uniformly steep, and unforgiving from base to summit. Respect the average, prepare for the maximum, and gear low.

Length: 10.1 km
Average gradient: 10.49%
Max gradient: 19.31%
Start: 100 m
Summit: 1159 m
Net gain: 1059 m
Total ascent: 1014 m
Category: HC