Collada de Arnicio

Overview

Collada de Arnicio is a Category 2 climb in Spain, running 16.1 km from base to summit. On paper it is a moderate effort: the net elevation gain is 653 m, rising from a start elevation of 254 m to a summit at 907 m. The average gradient of 4.06% suggests a steady, unthreatening drag that most riders could sit and spin.

That average is misleading. The total ascent over the 16.1 km is 1,654 m — more than two and a half times the 653 m of net gain. The difference means roughly 1,001 m of descending is folded into the climb. You are not grinding uphill the whole way; you are repeatedly climbing, giving back altitude, and climbing again. That undulation makes the true climbing gradient far steeper than 4.06%, and it fragments any rhythm you try to build.

How the Gradient Unfolds

The 4.06% average is an accounting artifact of all that lost and regained elevation. Because 1,654 m of ascent is packed into a route that only nets 653 m, the pitches that actually go up are considerably steeper than the headline figure. Expect the effort to arrive in bursts rather than as one long, even wall.

• Flatter and descending recovery sections between the harder pitches, where the road gives back elevation.
• Repeated short climbs stacked back to back, each resetting your legs before the next.
• Steeper ramps on the true climbing segments, well above the 4.06% average, that demand a jump in power.

Pacing Notes

On a smooth, even climb you can hold a single sustainable power output from bottom to top. Arnicio does not reward that approach cleanly. The descents and flat sections mean even-speed pacing would have you soft-pedalling downhill and then spiking hard on every ramp — an inefficient, surging effort.

Aim instead for even effort on the climbing pitches: pick a wattage you can repeat across each short rise, and use the recovery sections to genuinely recover rather than to push. Because the ramps are steeper than the average, know your ceiling before you start. Run the FTP estimator so you can set a target you can hold across repeated efforts without burning through your reserves on the first steep section.

Gearing

Because the true climbing pitches are steeper than the 4.06% average implies, gear for the ramps, not the mean. A compact or sub-compact chainset paired with a wide-range cassette gives you the low end to stay seated and spinning when the road kicks up. A 34×32 or 34×34 combination keeps your cadence up on the steeper segments so you protect your legs for the repeated efforts. Check your setup before the ride — confirm your smallest chainring and largest sprocket now, not on the first ramp.

Summary

• Length: 16.1 km
• Average gradient: 4.06%
• Net elevation gain: 653 m
• Total ascent: 1,654 m
• Category: 2

Collada de Arnicio is a climb defined by its undulation. The modest 653 m net gain understates a route that asks for 1,654 m of total climbing across repeated short efforts. Pace by effort, gear for the ramps, and treat the average gradient as the least useful number here.