Alto del Corral del Diablo

Overview

Alto del Corral del Diablo is an hors catégorie climb, the hardest classification on the scale, and its numbers explain why. Over 12 km the road gains 1191 m of net elevation, lifting you from a start at 1166 m to a summit at 2357 m. The average gradient is a relentless 9.9%, and the total ascent of 1149 m confirms there is barely any respite baked into those kilometers. This is a climb that does not flatter you into a rhythm and then let go — it simply keeps tilting upward.

How the Gradient Unfolds

An average of 9.9% across 12 km is severe on its own, but averages hide the teeth. With a maximum gradient of 31.37%, this climb contains ramps steep enough to force you out of the saddle or, on a bad day, to a standstill. The gap between the 9.9% average and the 31.37% peak tells you the pitch is uneven: stretches near the mean will feel almost merciful compared to the walls. Because net gain (1191 m) sits close to total ascent (1149 m), there is very little descending or flat to recover on. Expect to be climbing continuously, with the hardest ramps punishing any moment you let the pace sag.

Pacing Notes

On a climb this long and steep, discipline early is everything. The temptation is to attack the lower slopes while your legs feel fresh, but with 12 km and 1191 m still to gain, overcooking the first third is the classic way to blow up before the summit at 2357 m. Anchor your effort to your FTP and hold a sustainable percentage of it, treating the 31.37% ramps as brief surges to survive rather than efforts to conquer. If you are unsure what number to ride to, run your figures through the FTP estimator before you commit to the mountain. Note that the summit sits at 2357 m — thin air at altitude will quietly erode your ceiling, so plan to ride slightly more conservatively than sea-level power would suggest.

Gearing

Do not under-gear this one. A 9.9% average sustained for 12 km, spiking to 31.37%, demands the lowest ratios most riders can fit. A compact 34×32 is the practical minimum here, and even strong climbers will be grinding on the steepest pitches. For most riders a 34×34 is the wiser choice, buying you a cadence you can actually turn on the walls instead of lurching in a too-big gear. If your bike accepts an even larger cassette, take it — on a climb rising 1191 m with ramps past 31%, spare gears are never wasted.

Summary

Alto del Corral del Diablo earns its HC billing honestly: 12 km, an unyielding 9.9% average, a savage 31.37% max, and 1191 m of net elevation to a 2357 m summit. Gear low, pace with your head, and respect the ramps.

Length: 12 km
Average gradient: 9.9%
Max gradient: 31.37%
Start: 1166 m
Summit: 2357 m
Net gain: 1191 m
Total ascent: 1149 m
Category: HC