Buztanzelaiko lepoa

Overview

Buztanzelaiko lepoa is a short climb that refuses to give anything away. Over 6.9 km it averages 10.23%, a figure that puts it firmly among the toughest sustained gradients you can ride. From a start elevation of 163 m it rises to a summit of 872 m, a net gain of 709 m packed into under seven kilometres. Rated category 1, it sits just one rung below hors catégorie, and the double-digit average tells you exactly why. There is no gentle valley approach and no false summit to hide behind, just a road that tilts up and stays there.

How the Gradient Unfolds

The defining number here is not the length but the slope. A 10.23% average across 6.9 km means the climb almost never eases below the point where you are fighting gravity outright. The maximum gradient of 25.03% is the sting in the tail: a pitch more than twice the average, steep enough to bring most riders out of the saddle whether they want to be there or not. With a net elevation gain of 709 m against a total ascent of 668 m, the profile is almost entirely uphill, with only a small amount of the climbing coming back through minor dips. Expect the gradient to hover in the low-to-mid teens through the meat of the ascent, punctuated by ramps that spike well beyond that toward the 25.03% maximum.

Pacing Notes

On a climb this steep, pacing is survival. The key is to hold an even effort just below your threshold and resist the urge to attack the early ramps. Your FTP is the anchor number: ride the sustained sections at or fractionally under it, and keep something in reserve for the pitches climbing toward 25.03%, where power and cadence both spike. If you are not sure what your threshold is, run the numbers through the FTP estimator before you go, then translate that into a target you can hold for the roughly 30 to 45 minutes this climb will demand. Going into the red on the lower slopes is the classic mistake; on a 10.23% average there is no flat to recover on.

Gearing

Gear for the steepest pitch, not the average. On a climb that touches 25.03%, most riders will want a compact chainset paired with a wide-range cassette. A 34×32 is the sensible baseline and will get many riders up the sustained 10.23% sections, but for the ramps near the maximum a 34×34 buys you crucial extra range and lets you spin rather than grind. If your legs or your bike allow anything easier, take it — you will not regret spare gears on 709 m of near-continuous climbing.

Summary

Buztanzelaiko lepoa is a pure, uncompromising climb: short in distance, brutal in gradient, and unrelenting from bottom to top. Come with low gears, a disciplined pacing plan, and respect for that 25.03% maximum.

Length: 6.9 km
Average gradient: 10.23%
Max gradient: 25.03%
Start: 163 m
Summit: 872 m
Net gain: 709 m
Total ascent: 668 m
Category: 1