Puerto de Ulzurrun

Overview

Puerto de Ulzurrun is a category 2 climb that packs a genuine day's effort into a compact 8 km. From the foot at 409 m, the road rises to a summit of 859 m — a net gain of 450 m — at an average gradient of 5.64%. That average is honest rather than gentle: it sits in the range where you can hold a rhythm, but only if you resist the urge to force the pace early. With a maximum pitch of 8.83%, there is enough bite here to punish riders who arrive at the steep sections already over their limit.

How the Gradient Unfolds

The story of this climb is the gap between its 5.64% average and its 8.83% ceiling. A steady 5.64% would be a metronomic tempo effort; the reality is that the slope leans harder in places, so the true experience swings above and below the mean. Expect stretches where the road eases and lets you recover, offset by ramps climbing toward that 8.83% figure that force a sharp change of cadence. Over 8 km, those swings are what fatigue you — not the length alone. The total ascent of 428 m sits just under the 450 m net gain, telling you this is a near-continuous climb with little false descent to break the effort.

Pacing Notes

The smart approach is to pace against your sustainable power rather than the gradient in front of you. Anchor your effort to your FTP: on the shallower sections aim to sit just below threshold, then let your power drift up over it briefly on the ramps toward 8.83% before settling again. Because the climb is only 8 km, you can afford to run slightly richer than you would on a longer col — but going deep in the first kilometre still costs you dearly across the back half. If you are unsure of your threshold, run the numbers through the FTP estimator before you plan your target. Keep something in reserve for the steepest pitches, where holding cadence matters more than raw speed.

Gearing

For a climb averaging 5.64% and touching 8.83%, most riders will want a compact setup with a generous cassette. A 34×32 bottom gear is a sensible baseline: it lets you spin the steeper ramps without grinding, and it keeps your cadence high enough to protect your legs across the full 8 km. If you tend to climb at a lower cadence, carry extra weight, or simply want insurance for the 8.83% sections late in the effort, step up to 34×34. That extra sprocket costs nothing on the shallower gradients and buys real comfort when the road pitches up with tired legs.

Summary

Puerto de Ulzurrun rewards patience: pace it against your threshold, gear it to spin the steep ramps, and let the 450 m of climbing come to you across its 8 km. It is a category 2 test that stays honest from bottom to top.

Length: 8 km
Average gradient: 5.64%
Max gradient: 8.83%
Start: 409 m
Summit: 859 m
Net gain: 450 m
Total ascent: 428 m
Category: 2