Alto de las Coles

Overview

Alto de las Coles is a climb that gives you nowhere to hide. Over 11 km it averages 8.98%, and an average that steep sustained over that distance is what earns a road its HC rating — hors catégorie, beyond classification, the hardest label the sport hands out. You start at 710 m and finish at 1694 m, a summit elevation gained through 984 m of net vertical. The total ascent of 960 m tells you the road climbs almost relentlessly upward with only fractional relief.

The headline number that reshapes everything is the 25.6% max gradient. A pitch that severe is not a passing detail; it is a wall you have to plan your entire effort around.

How the Gradient Unfolds

Think of this climb in terms of its shape rather than its scenery. With an 8.98% average across 11 km, there is no long false-flat to recover on — the road simply keeps tilting. The gap between the 8.98% average and the 25.6% maximum is the story: when a climb spikes nearly seventeen points above its own average, it means the steepest ramps are dramatically harder than the "typical" gradient your legs settle into.

That structure rewards riders who can hold a steady tempo and then absorb sharp surges without blowing apart. The 984 m of net gain arrives in a near-continuous stack — the small difference between 984 m net and 960 m total ascent confirms there is essentially no descending to break the rhythm. Every metre you climb, you keep.

Pacing Notes

On a climb this long and steep, pacing is survival. Anchor your effort to your FTP and resist the urge to chase the early gradient. At 8.98% average you will be near or above threshold from the first kilometre, so the discipline is holding a sustainable output and saving a reserve for the 25.6% ramp, where cadence collapses and torque demand spikes.

If you do not know your threshold precisely, run the numbers through the FTP estimator before you commit to a target. Meter the first several kilometres slightly under what feels possible; an 11 km sustained effort punishes anyone who overcooks the opening. On the steepest pitch, shift early, stay seated where you can for traction, and let the gearing — not raw force — carry you over.

Gearing

Do not under-gear this one. For most riders, a compact 34-tooth chainring paired with a wide cassette is the sensible floor here. A 34×32 will get many fit climbers up the sustained 8.98% sections, but the 25.6% maximum is where a 34×32 can leave you grinding at a cadence low enough to threaten traction and knees alike.

If your setup allows it, a 34×34 gives you that extra margin exactly where you need it — on the wall. The lower gear lets you spin rather than heave, protecting both your legs over the full 984 m of climbing and your rear wheel's grip on the steepest ramp. When in doubt on an HC climb, choose the easier gear.

Summary

Alto de las Coles is a pure HC test: long, steep, and punctuated by a ramp severe enough to redraw your pacing plan. Respect the 8.98% average, gear for the 25.6% maximum, and meter the effort across all 11 km. Do that, and the 1694 m summit is yours.

Length: 11 km
Average gradient: 8.98%
Max gradient: 25.6%
Start: 710 m
Summit: 1694 m
Net gain: 984 m
Total ascent: 960 m
Category: HC