Alto de Conejo

Overview

Alto de Conejo is a hors catégorie climb that earns every letter of that label. Over 20.5 km it averages 8.47%, dragging you from a start elevation of 2209 m all the way to a 3942 m summit. That is 1733 m of net elevation gain, with 1699 m of total ascent packed into a road that almost never lets up. There is no easing-in ramp, no valley cruise to warm the legs — the average gradient alone tells you this is a sustained, grinding effort at altitude, where thin air steals watts you did not know you had.

How the Gradient Unfolds

The defining number here is consistency. An 8.47% average across 20.5 km means there is very little relief on offer; if the road backed off anywhere, it would have to spike viciously elsewhere to hold that mean. The spikes exist — the gradient bites up to a max of 15.3% — but the story is less about a single wall and more about relentlessness. You climb, you keep climbing, and the elevation counter simply does not stop. Because the net gain (1733 m) slightly exceeds the total ascent figure of 1699 m in the way these are measured, expect a road that trends almost purely upward with negligible descending to reset your legs. The final third, above 3500 m, is where the altitude compounds the gradient and the climb feels hardest even where the slope has not changed.

Pacing Notes

At altitude, discipline is everything. Your sustainable power will be lower here than at sea level, so pace off effort and breathing rather than a flatland power number. Anchor your first hour to a fraction below your FTP — the pitches to 15.3% will punish anyone who burns matches early, because there is no flat to recover on for 20.5 km. If you do not know your threshold, run the numbers through the FTP estimator before you commit to a target. On a climb this long and this high, going out five percent too hard in the first quarter turns the final push above 3500 m into damage control.

Gearing

Do not under-gear this one. With a sustained 8.47% average and ramps to 15.3% — all above 2209 m where every pedal stroke costs more — you want spin, not grind. A compact 34-tooth chainring paired with a wide-range cassette is the sensible baseline. A 34×32 is the minimum I would ride here, and even strong climbers will be grateful for a 34×34 (or lower) once fatigue and altitude stack up in the closing kilometres. The goal is to keep cadence high enough to protect your legs across a full 20.5 km of climbing rather than muscling a big gear early and paying for it near 3942 m.

Summary

Alto de Conejo is a pure test of altitude endurance: long, steep, and unforgiving from bottom to top. Respect the pacing, gear low, and let the summit come to you.

Length: 20.5 km
Average gradient: 8.47%
Max gradient: 15.3%
Start: 2209 m
Summit: 3942 m
Net gain: 1733 m
Total ascent: 1699 m
Category: HC