Alto de Arrayan

Overview

Alto de Arrayan is a genuine hors catégorie climb, and the numbers make no apology for it. Over 11.6 km the road averages 10.28%, hauling you from a start elevation of 992 m to a summit at 2183 m. That is a net gain of 1191 m, with 1162 m of total ascent counted along the way. Almost every metre of this climb points relentlessly uphill; there is very little rolling relief to hide behind. A double-digit average over that distance places Arrayan firmly among the hardest paved climbs a rider will ever attempt, and the HC rating is fully earned rather than generously awarded.

How the Gradient Unfolds

The defining feature here is not a single monster ramp but sustained, unbroken steepness. With an average of 10.28% and a max of 22.07%, the climb rarely offers a gradient you would call comfortable. The 22.07% pitch is the sharpest tooth on the mountain, and even the shallower stretches sit well above what most riders consider a recovery gradient. Because the net gain of 1191 m is only slightly above the total ascent of 1162 m, you can read the profile as almost purely upward: nearly no descending, no false flats to spin out on. Treat the whole 11.6 km as one continuous effort, and expect the steepest ramps to arrive without much warning.

Pacing Notes

On a climb this long and this steep, pacing is survival. Anchor your effort to FTP rather than feel, because the sustained 10.28% average will punish anyone who starts hot. Aim to hold a steady, sub-threshold power for the bulk of the 11.6 km, keeping a small reserve for the 22.07% wall where cadence collapses and torque spikes. If you do not know your threshold number, run the FTP estimator before you attempt Arrayan so you can set realistic power ceilings. The rule is simple: never redline early. With 1191 m still to climb from the bottom, an over-eager first third leaves nothing for the summit.

Gearing

Gear for the max, not the average. A 22.07% pitch on tired legs demands the lowest ratios you can fit. A compact 34-tooth chainring paired with a 34×32 cassette combination is the minimum I would recommend for most riders here, and many will be far happier with 34×34. On a climb that averages 10.28% for 11.6 km, the extra sprocket is not indulgence — it is what keeps your cadence high enough to protect your knees and your composure. If your bike can take it, give yourself the 34×34; you will spend a long time at low speed on this mountain, and easier gearing turns a grim grind into something survivable.

Summary

Alto de Arrayan is an uncompromising HC ascent: long, steep, and unyielding from base to summit. Respect the 10.28% average, gear low for the 22.07% wall, and pace to your threshold. Do that, and 2183 m is within reach.

Length: 11.6 km
Average gradient: 10.28%
Max gradient: 22.07%
Start: 992 m
Summit: 2183 m
Net gain: 1191 m
Total ascent: 1162 m
Category: HC