Collado de Halda

Overview

Collado de Halda is a Category 3 climb in Spain, running 10.5 km from a start elevation of 96 m up to a summit at 451 m. That gives a net elevation gain of 355 m and an average gradient of 3.37% — firmly in the territory of a long, steady drag rather than a wall. It is the kind of ascent you can hold a rhythm on, provided you read the profile rather than the average.

The number that matters most here is the gap between net gain and total ascent. You climb 355 m net, but the road actually asks for 456 m of total ascent — roughly 101 m of extra climbing swallowed by descents and dips along the way. That undulation means you are repeatedly losing and regaining height, so the effort is punchier than a smooth 3.37% grade would suggest. Every dip you coast into is height you have to buy back.

How the Gradient Unfolds

The 3.37% average is a blend, not a constant. With a maximum gradient of 10.37%, there are pitches more than three times steeper than the mean, and those ramps are where the climb bites. Between them sit flatter and even descending sections that pull the average down but break your rhythm.

• Flatter and recovery sections where you can shift up and spin
• Repeated short climbs stacked between the dips — the source of that 101 m of extra ascent
• A steepest ramp near 10.37% that demands a real gear change

Pacing Notes

On an undulating climb like this, chasing an even speed is a trap — you will over-cook every ramp and freewheel the descents. Aim instead for even effort, holding a steady sustainable power output through the steep pitches and letting your speed rise naturally on the flatter stretches. Do not attack the descents; use them to recover.

Know your numbers before you go. Run the FTP estimator so you can anchor your target watts, then hold that ceiling on the 10.37% ramp rather than spiking over it and paying for it later.

Gearing

The average is friendly, but gearing is governed by the steepest gradient, and 10.37% at the end of a 10.5 km effort is enough to grind you down on the wrong setup. A compact (50/34) or sub-compact chainset paired with a wide-range cassette — something like a 34×32 or 34×34 — gives you a bail-out gear for the ramps without spinning out on the flats. Check your chainset and cassette before the ride; do not discover you are under-geared halfway up.

Summary

• Length: 10.5 km
• Average gradient: 3.37%
• Maximum gradient: 10.37%
• Net elevation gain: 355 m
• Total ascent: 456 m
• Category: 3

Collado de Halda rewards riders who pace to the profile, not the average. Hold even effort through the ramps, recover on the dips, and come geared for the 10.37% pitch — do that and the extra 101 m of undulation stays a footnote rather than the story.