Alto de Errea

Overview

Alto de Errea is a category-2 climb that packs a serious punch into a compact 4.6 km. From the base at 513 m it rises to a summit of 847 m, a net gain of 334 m, with the recorded total ascent coming in at 319 m. The headline number is the average gradient: 7.19% held across the full 4.6 km. That is a demanding, sustained figure rather than a rolling one, and it means there is very little respite from base to top.

With a maximum gradient of 8.31%, Errea does not rely on a single brutal ramp to earn its category. Instead, the difficulty comes from consistency. The gap between the 7.19% average and the 8.31% peak is only just over a point, which tells you almost the entire climb sits close to that hard, steady baseline.

How the Gradient Unfolds

The shape of Errea is best understood through the narrow spread between its average and maximum. When a climb averages 7.19% and tops out at 8.31%, the road is essentially one long, even wall. There are no flat recovery sections hiding in the profile and no soft lower slopes to spin through before the real work begins.

Expect the gradient to bite from early and stay there. The steepest stretches, at 8.31%, will feel like a modest step up from the average rather than a shock. Over 4.6 km of continuous climbing, that relentlessness is the defining challenge — your legs never get the micro-rests that a lumpier profile would hand out. Ride it as a single effort, not a series of surges.

Pacing Notes

Because the gradient is so even, Errea rewards a disciplined, threshold-style approach. This is a climb to pace off your FTP rather than your ego. Settle into a sustainable power just below or at threshold from the base and hold it — the lack of variation means any early over-effort will haunt you long before the 847 m summit.

If you are not sure where your threshold sits, run the numbers through the FTP estimator before you plan the effort. On a 4.6 km climb at 7.19%, the difference between the right target power and a guess is the difference between a smooth ascent and blowing up two-thirds of the way up. Keep your cadence steady, breathe to a rhythm, and treat the 8.31% pitches as brief taxes on an otherwise even effort.

Gearing

For a sustained 7.19% average that stiffens to 8.31%, gearing that lets you keep cadence up is the priority. A compact 34-tooth inner chainring paired with a 32-tooth largest sprocket (34×32) is a sensible baseline for strong climbers who want to spin rather than grind the steady grade.

If you carry any fatigue, ride at a lower weight-to-power, or simply prefer a higher cadence on long even walls, size up to a 34×34. That extra sprocket makes the difference on a climb where the gradient never eases — over 4.6 km, protecting your cadence and your knees is worth more than a marginally taller top gear you will not use.

Summary

Alto de Errea is a short but honest category-2 test: 4.6 km of consistent 7.19% climbing with a maximum only marginally steeper. It is a climb of rhythm and pacing, not surprises. Pick a threshold effort, gear to spin, and hold form to the top.

Length 4.6 km
Average gradient 7.19%
Max gradient 8.31%
Start 513 m
Summit 847 m
Net gain 334 m
Total ascent 319 m
Category 2