Collado Achuela

Overview

Collado Achuela is a Category 2 climb in Spain, running 8.4 km from a start elevation of 326 m to a summit at 770 m. On paper it delivers a net elevation gain of 444 m at an average gradient of 5.28% — numbers that read like a steady tempo effort you can settle into and hold to the top.

The profile tells a different story. Total ascent over the climb is 803 m, roughly 359 m more than the net gain suggests. That gap is undulation: the road repeatedly gives back height before clawing it back again. Every metre of that extra ascent is work your legs still have to do, so the climb costs more energy than its net figures imply. Treat it as a harder effort than the 5.28% average would lead you to expect.

How the Gradient Unfolds

A 5.28% average on a climb that actually ascends 803 m means the gradient is uneven by design. Flatter and downhill sections drag the average down, which in turn masks steeper pitches — the standout being a 22.7% maximum ramp that will overwhelm any rider trying to hold a fixed cadence.

• Recovery sections where the road flattens or descends, dropping the working gradient well below 5.28%
• Repeated short climbs that rebuild the height you just lost, stacking on top of the 444 m net gain
• A steepest ramp hitting 22.7% — a brief but decisive spike that dictates your gearing choice

Pacing Notes

On an undulating climb like this, pace by effort, not by speed. Even-speed pacing forces you to bury yourself on every kicker and coast on the flatter sections — exactly wrong here, given how many kickers there are. Instead, hold a steady effort just below your sustainable power output: let your speed rise on the shallow bits and fall on the ramps while the effort stays flat.

If you don't know that ceiling, run the FTP estimator before you go. Anchor your climb to a number you can defend for the full 8.4 km, and resist the urge to chase the 359 m of hidden ascent with matching surges.

Gearing

The 22.7% maximum ramp governs your setup. That gradient is too steep for a standard chainset held at a workable cadence — gear for it or grind to a halt. Run a compact or sub-compact chainset paired with a wide-range cassette; a 34×32 or 34×34 low gear gives you the room to spin the steepest pitch rather than muscle it. Check your chainrings and cassette before the ride — the summit is a poor place to discover you're overgeared.

Summary

• Length: 8.4 km
• Average gradient: 5.28%
• Maximum gradient: 22.7%
• Net elevation gain: 444 m
• Total ascent: 803 m
• Category: 2

Collado Achuela is a climb that punishes riders who trust the average. Respect the undulation, gear for the 22.7% ramp, and pace by effort — do that and its 803 m of climbing becomes manageable rather than merciless.