Puerto de Sarrablo

Overview

Puerto de Sarrablo is a Category 1 climb that measures 11.9 km from base to summit, gaining 706 m of net elevation as it rises from 593 m to a top of 1299 m. The average gradient sits at 5.92%, which places it firmly in the sustained-effort bracket: steep enough to demand respect, but not so unrelenting that it turns into a pure survival exercise. With a maximum pitch of 12.88% and 688 m of total ascent packed into its length, this is a climb that rewards riders who can hold a steady rhythm over a long, continuous effort. The Category 1 label tells you where it lands on the scale — one step below hors catégorie, and comfortably harder than the Category 2, 3 and 4 climbs you might use as warm-ups.

How the Gradient Unfolds

The headline number is 5.92%, but averages hide the texture. Across 11.9 km, the difference between the net gain of 706 m and the total ascent of 688 m is small, which tells you the road climbs almost continuously with very little downhill relief to break the effort. That consistency is the defining feature: you are rarely coasting. The steepest recorded ramp reaches 12.88%, more than double the average, so expect at least one stretch where the gradient bites well above what your legs have settled into. Around those pitches the road eases back toward the 5.92% mean, giving you brief windows to recover your cadence before the next lift. Treat the climb as one long, grinding block punctuated by sharper kicks rather than a series of distinct terraces.

Pacing Notes

On an effort this long, pacing is everything. Aim to settle into a power that sits just below your threshold and hold it — surging on the 12.88% ramp only to blow up two kilometres later is the classic mistake here. Anchor your target to your FTP: for a Category 1 climb of 11.9 km, most riders should sit a touch under threshold on the average slopes and let power drift up only through the steep sections. If you do not know your number, run the FTP estimator before you plan your effort. With 706 m to gain, patience early pays back on the upper slopes where the accumulated 688 m of ascent starts to tell.

Gearing

For 11.9 km at 5.92% with pitches to 12.88%, gear for the steepest section, not the average. A compact 34-tooth chainring paired with a 34×32 low gear will get most trained riders up the climb, but if you plan to protect your legs or you weigh toward the higher end, step up to a 34×34. That extra sprocket keeps your cadence intact when the 12.88% ramp arrives, so you spin rather than grind. The difference between 34×32 and 34×34 is small on paper but decisive over a 706 m ascent.

Summary

Puerto de Sarrablo is a genuine Category 1 test: 11.9 km of near-continuous climbing at 5.92%, topping out at 1299 m after 706 m of net gain. Pace it patiently, gear for the 12.88% ramp, and it rewards you.

Length: 11.9 km
Average gradient: 5.92%
Max gradient: 12.88%
Start: 593 m
Summit: 1299 m
Net gain: 706 m
Total ascent: 688 m
Category: 1