Alto del Espino

Overview

Alto del Espino is a genuine hors catégorie (HC) beast — the hardest rating there is, sitting above categories 1 through 4. Over 17 km it averages a punishing 9.65%, hauling you from a start at 868 m to a summit of 2513 m. That is a net gain of 1645 m, with 1683 m of total ascent once the handful of small dips are added back in. Nothing about this climb is casual. An average approaching double digits sustained across 17 km puts it in the company of the most feared ascents anywhere, and the thin air near the 2513 m top only sharpens the sting.

How the Gradient Unfolds

The number that reframes everything is the maximum gradient: 27.77%. That is close to three times the average, so the mean of 9.65% hides savage variation. Expect the road to swing between merely hard and near-vertical, and plan for those spikes rather than being ambushed by them.

The math tells the honest story. Net gain is 1645 m but total ascent is 1683 m — a difference of 38 m of bonus climbing tucked into brief descents or flatter shelves that break the wall. Those respites are small. For the overwhelming majority of the 17 km you are pointed relentlessly uphill, and the ramps toward 27.77% will demand everything your legs and gearing can offer.

Pacing Notes

On a climb this long and steep, discipline beats bravado. Your single most useful reference is your FTP — the sustainable power that determines whether you finish strong or blow apart on the upper slopes. At 17 km, an HC effort can run well past an hour, so ride the early kilometers a touch below what feels comfortable. The pitches toward 27.77% will spike your power involuntarily; bank patience so you have headroom left when they arrive.

If you are unsure of your number, run the FTP estimator before you commit to a pacing plan. Set a realistic target for the full 17 km and let the steep sections pull you above it briefly rather than trying to hold a flat wattage that the terrain simply will not allow.

Gearing

Do not under-gear for Alto del Espino. With a 9.65% average and ramps to 27.77%, a compact 34-tooth chainring is the sensible front choice, paired with the widest cassette you can fit. A 34×32 is the minimum I would suggest for the merely steep stretches, and even that will feel tall when the road tilts toward its maximum. For most riders a 34×34 is the smarter call — that extra sprocket buys precious cadence on the near-vertical pitches and protects your knees across the full 1645 m of climbing. If your frame accepts an even wider range, use it. On an HC climb of this length, spinning survives where grinding fails.

Summary

Alto del Espino is a summit-hunter's trophy and a leg-breaker in equal measure: 17 km, 9.65% average, a wall-like 27.77% max, and 1645 m of vertical between 868 m and 2513 m. Respect the numbers, gear low, pace with your FTP, and it becomes one of the most rewarding HC efforts you can chase.

Length: 17 km
Average gradient: 9.65%
Max gradient: 27.77%
Start: 868 m
Summit: 2513 m
Net gain: 1645 m
Total ascent: 1683 m
Category: HC