Coll de Xemeneies

Overview

Coll de Xemeneies is a hors catégorie climb that belongs in the conversation of Europe's hardest paved ascents. Over 12.7 km it hauls you from a start elevation of 953 m to a summit at 2362 m, a net elevation gain of 1409 m. The average gradient reads 11.11% — a figure that, sustained across nearly thirteen kilometres, leaves almost nowhere to recover. Where most HC climbs offer flatter breathers to reset the legs, Xemeneies simply keeps tilting upward. The total ascent of 1343 m confirms there is precious little descending mixed in; nearly everything you climb, you keep. This is a climb defined by its unrelenting shape rather than any single feature.

How the Gradient Unfolds

The defining characteristic here is consistency of severity. An 11.11% average is not built from a gentle run-up and one savage finish — it is built from a slope that rarely drops into single digits. The pitch peaks at a wall of 28.12%, more than double the average, which means somewhere on this climb the road rears up to a gradient most riders can barely walk. Because the net gain (1409 m) exceeds the total ascent (1343 m) only in the sense that both are enormous over 12.7 km, you should expect the grade to stay punishingly high from bottom to top. Plan your effort around the assumption that the road never truly relents, and treat any easing as a gift rather than a right.

Pacing Notes

On a climb this steep and this long, pacing is everything. Ride within your FTP from the first ramps — going into the red on the lower slopes here is unrecoverable, because there is no shallow section ahead to bail you out. If you do not know your threshold, run the numbers first with the FTP estimator so you can set a realistic ceiling. On an 11.11% average, gravity dictates a slow cadence and a high torque demand, so aim to keep your power just under threshold and hold it steady. The 28.12% pitch will force a brief, unavoidable surge above your target — accept it, then settle straight back down. Fuel early and often; at these gradients you are burning through reserves long before the 2362 m summit.

Gearing

Do not under-gear this climb. With an 11.11% average and a 28.12% maximum, the standard compact-and-easy setup that works on ordinary HC climbs will leave you grinding. A 34×32 is the realistic minimum, and even then the steepest ramps will feel brutal at low cadence. For most riders a 34×34 is the smarter choice, buying you enough range to spin the 28.12% wall rather than lurch across it. If your bike accepts anything easier still, use it — there is no penalty for spare gears on a slope this steep, only regret for the ones you lack.

Summary

Coll de Xemeneies is a pure test of sustained climbing: long, savagely steep, and honest from base to summit. Respect the gradient, gear low, and pace conservatively, and 1409 m of climbing becomes an achievement rather than a disaster.

Length: 12.7 km
Average gradient: 11.11%
Max gradient: 28.12%
Start: 953 m
Summit: 2362 m
Net gain: 1409 m
Total ascent: 1343 m
Category: HC