Alto del Pozo

Overview

Alto del Pozo is a hors catégorie (HC) climb, the hardest classification a road ascent can carry, and its numbers explain why. Over 34.1 km the road lifts you from a start elevation of 717 m to a summit at 2414 m — a net elevation gain of 1697 m. That length alone places it in the rarefied company of the world's longest paved climbs. The average gradient of 4.98% sounds almost gentle in isolation, but sustained across 34.1 km it becomes an hour-plus effort at threshold for even strong climbers. This is a diesel's climb: a test of patience, fueling, and pacing discipline far more than raw punch.

How the Gradient Unfolds

The headline average of 4.98% hides real variation. With a maximum gradient of 10.5%, there are pitches more than twice as steep as the mean — enough to break your rhythm if you attack them. Notice too that the total ascent (1715 m) exceeds the net elevation gain (1697 m) by 18 m. That 18 m of difference is metres of climbing you do twice: brief false flats, dips, or descents scattered through the 34.1 km where the road gives back a little altitude before clawing it back again. Expect the profile to breathe — ramps toward that 10.5% ceiling, then shallower sections well below the average where you can recover without stopping.

Pacing Notes

At 34.1 km this is fundamentally a threshold exercise, so ride it by the numbers. Your best guide is your FTP: settling in a hair below it lets you absorb the steeper 10.5% ramps without redlining, then relax on the shallow stretches. Because the effort spans more than an hour, going even a few percent too hard early compounds badly over 1697 m of gain. If you're unsure of your current threshold, run the numbers through the FTP estimator before you commit to a target. Resist the urge to chase the steep pitches — let them come to you, hold your power steady, and let the 4.98% average do its slow work.

Gearing

Gear for the duration, not just the maximum slope. With 1715 m of total ascent and pitches to 10.5%, you want low ratios you can spin for over an hour. A compact 34-tooth chainring paired with a wide cassette is the sensible baseline: a 34×32 covers most of the climb comfortably, but on a summit approaching 2414 m — where thinner air saps power — a 34×34 gives you the extra margin to keep cadence up on the 10.5% ramps late in the effort. If your legs or altitude tolerance are in doubt, err toward the easier gear.

Summary

Alto del Pozo rewards patience above all. It is long, steady, and unforgiving of a poor start — a genuine HC climb where holding a smart, sub-threshold pace across 34.1 km matters more than any single surge.

Length: 34.1 km
Average gradient: 4.98%
Max gradient: 10.5%
Start: 717 m
Summit: 2414 m
Net gain: 1697 m
Total ascent: 1715 m
Category: HC