Coll del Bruc

Overview

Coll del Bruc is a long, patient Category 2 climb that trades brute steepness for sheer duration. Over 21 km the road lifts you from a valley floor at 87 m to a summit of 760 m — a net gain of 673 m — at an average gradient of just 3.21%. On paper that number looks gentle, and for long stretches it is. But 21 km is a long time in the saddle, and the total ascent of 700 m tells you the road is not a single clean ramp: it rolls, dips, and reloads more than once. The category-2 rating is earned by length and by one savage pitch, not by relentless wall gradients. Come with a rhythm, not a sprint.

How the Gradient Unfolds

A 3.21% average across 21 km means most of this climb sits well inside your comfort zone — shallow enough to hold a big gear and keep momentum. The gap between the 673 m net gain and the 700 m of total ascent reveals the shape: there are false flats and small descents that give elevation back before you climb it again. That extra 27 m of "wasted" climbing is where a long day quietly drains your legs. The defining feature is the max gradient of 17.51% — a spike more than five times steeper than the average. It arrives as a shock against the mellow backdrop, and it is the single moment on Coll del Bruc where survival, not speed, becomes the priority.

Pacing Notes

Because the average is so low, the temptation is to attack from the base. Resist it. Your target for a climb this long should be a fraction under threshold — sitting just below your FTP so you have headroom left for the 17.51% ramp. If you do not know your threshold number, run the numbers through the FTP estimator before you go, then ride the shallow sections at a strong tempo and save a matchstick for the steep pitch. On the 3.21% grades, keep cadence high and let the road do some of the work; the real cost here is time, not gradient. When the 17.51% wall hits, drop early, spin what you can, and get back into rhythm the moment it relents.

Gearing

The 3.21% average will not force your hand — a mid-cassette gear covers most of the climb comfortably. The problem is the 17.51% max. A compact chainring paired with a 34×32 low gear is the sensible baseline for most riders tackling 21 km with a spike this sharp. If you climb on tired legs, spin a low cadence, or simply want insurance, size up to a 34×34 so that steep ramp never drops you below a turnable gear. On a climb defined by duration, the wrong low gear turns one 17.51% pitch into the moment your whole day unravels — err generous.

Summary

Coll del Bruc rewards patience. It is 21 km of mostly gentle 3.21% gradient hiding one 17.51% sting, a Category 2 test of endurance far more than power. Pace it below threshold, gear for the spike, and the 673 m of net gain arrives without drama.

Length: 21 km
Average gradient: 3.21%
Max gradient: 17.51%
Start: 87 m
Summit: 760 m
Net gain: 673 m
Total ascent: 700 m
Category: 2