Collado del Asón

Overview

Collado del Asón is a category 2 climb that packs a serious punch into a compact package. Over 8.2 km it lifts you from a start elevation of 186 m to a summit of 686 m, a net gain of 500 m. The total ascent registers at 483 m, meaning the road climbs almost relentlessly with only slight relief along the way. At an average gradient of 6.07% it sits firmly in sustained-effort territory: steep enough to hurt, long enough to demand discipline, and topped with a max gradient of 10.38% that rewards anyone who paces the earlier slopes wisely.

How the Gradient Unfolds

The defining number here is the gap between average and maximum. A 6.07% mean across 8.2 km is honest, tempo-friendly climbing, but the 10.38% peak tells you the road is not uniform. Expect the effort to arrive in waves rather than a single steady drag. With 500 m of net gain but only 483 m of measured ascent, there is very little false flat or descent to hide in — nearly every metre of the road tilts upward. The steepest pitches, approaching that 10.38% ceiling, will spike your power and heart rate; the shallower sections nearer the average give you the only real windows to recover before the next ramp.

Pacing Notes

The smart approach on a climb like this is to anchor your effort to a target power rather than chasing the gradient. Aim to hold something at or just below your FTP on the sustained 6.07% sections, and accept that the 10.38% ramps will briefly push you above threshold — that is normal and sustainable over 8.2 km, provided you settle back down once the road eases.

If you do not know your threshold, run the numbers through the FTP estimator first so you have a concrete ceiling to ride against. With 500 m to gain and 483 m of ascent to grind through, going out too hard in the opening kilometres is the classic error. Start conservatively, keep your cadence high, and save a match for the steepest pitch.

Gearing

For a climb averaging 6.07% and spiking to 10.38%, gearing that lets you spin rather than grind is worth its weight. A compact 34-tooth chainring paired with a wide-range cassette is the sensible baseline. A 34×32 will cover most riders comfortably on the sustained sections and give you a fighting chance on the max-gradient ramps. If you prefer to keep your cadence up over all 8.2 km — or you are carrying fatigue into the climb — step down to a 34×34 for extra insurance on the steepest pitches. Neither is overkill on a category 2 effort with 500 m of climbing.

Summary

Collado del Asón is a well-defined category 2 test: 8.2 km, a genuine 6.07% average, and ramps to 10.38% that punish poor pacing. Manage your effort against threshold, gear low enough to spin, and the 500 m gain to the 686 m summit becomes a rhythm rather than a struggle.

Length: 8.2 km
Average gradient: 6.07%
Max gradient: 10.38%
Start: 186 m
Summit: 686 m
Net gain: 500 m
Total ascent: 483 m
Category: 2