Alto de Vacas

Overview

Alto de Vacas is a hors catégorie ascent, the hardest grade on the books, and the numbers explain why in a hurry. Over 13.2 km the road lifts you from a start elevation of 542 m to a summit at 1971 m — a net elevation gain of 1429 m and a total ascent of 1413 m once the small dips are accounted for. The average gradient is a brutal 10.79%, which is not the kind of figure you soft-pedal through. This is a climb defined almost entirely by its relentlessness: there is nowhere to hide across the full 13.2 km, and the summit at 1971 m arrives only after sustained, uninterrupted effort.

How the Gradient Unfolds

The defining feature here is the gap between the 10.79% average and the 38.84% maximum. A double-digit average already means the road rarely eases, but a max of 38.84% tells you that somewhere on this climb the surface pitches up to a wall that will overpower most riders who arrive at it with tired legs. Because the total ascent of 1413 m sits so close to the net gain of 1429 m, there are effectively no meaningful descents or flat recoveries built into the 13.2 km — what goes up simply keeps going up. Treat the whole climb as one long block of climbing punctuated by ramps that spike far above the average, and plan your effort so those spikes don't break you.

Pacing Notes

On a climb averaging 10.79% for 13.2 km, pacing is everything. Anchor your effort to your FTP and hold something in reserve, because the 38.84% max means you will need surges well above threshold to clear the steepest ramps without stalling. If you don't know your threshold number, run the numbers through the FTP estimator before you commit, then aim to sit just under threshold on the sustained 10.79% sections and spend matches only where the gradient forces you to. Starting too hard on a wall this long is the classic error — the net gain of 1429 m is unforgiving of an early blow-up.

Gearing

Gear for survival, not pride. With a 10.79% average and pitches reaching 38.84%, a compact chainring paired with a wide-range cassette is the minimum most riders should consider. A 34×32 gets you up the sustained sections, but on the steepest ramps a 34×34 gives you the extra spin you'll be grateful for. If your setup allows something even easier, use it — over 13.2 km and 1413 m of climbing, a cadence you can hold beats a heroic gear you can't turn.

Summary

Alto de Vacas is exactly what the HC label promises: long, steep, and unrelenting, gaining 1429 m over 13.2 km with ramps that touch 38.84%. Come prepared with low gears, a disciplined pace anchored to threshold, and respect for a climb that never lets up from 542 m to 1971 m.

Length: 13.2 km
Average gradient: 10.79%
Max gradient: 38.84%
Start: 542 m
Summit: 1971 m
Net gain: 1429 m
Total ascent: 1413 m
Category: HC