Puerto de los Pilones

Overview

Puerto de los Pilones is a category 1 climb that trades ferocity for sheer duration. At 39.9 km long it is one of those ascents where the challenge is measured in hours rather than minutes, and where the deciding factor is patience as much as power. From a start elevation of 145 m it winds up to a summit of 1747 m, delivering a net elevation gain of 1602 m. The average gradient reads a modest 4.01%, but that figure hides the real story: with a maximum pitch of 23.69%, the climb is anything but uniform. Total ascent comes in at 1716 m, slightly more than the net gain, which tells you the road undulates on its way up rather than climbing in one clean line.

How the Gradient Unfolds

The gap between the 4.01% average and the 23.69% maximum is the key to understanding this climb. An average that gentle across nearly 40 km means long stretches of shallow gradient, false flats, and possibly brief descents that give the road its 1716 m of total ascent against only 1602 m of net gain. Those recovery zones are a gift, but they also lull you into a rhythm that the steepest ramps will shatter. A pitch approaching 24% is severe enough to force you out of the saddle or drop you to walking pace if you arrive there with tired legs. Expect the effort to come in waves: easy tempo across the flatter kilometres, then sharp, concentrated bursts where the road rears up.

Pacing Notes

On a climb this long, discipline early is everything. Ride the shallow sections comfortably below your FTP, banking the low average gradient rather than burning matches on terrain that does not demand them. Save your surges for the steep ramps, where the 23.69% maximum will extract a real cost regardless of how you pace it. If you are unsure of your threshold, the FTP estimator will give you a working number to anchor your effort. Over 39.9 km and 1602 m of climbing, consistent, sustainable output beats heroics every time — go too hard on the flatter opening and the steep pitches late on will feel twice as cruel.

Gearing

The 4.01% average tempts you to bring a road-race setup, but the 23.69% maximum is what dictates your gearing. For most riders a 34×32 lowest gear is the sensible baseline here, giving you a bail-out ratio for the sharpest ramps without pushing awkward cadence on the shallow majority. If you tend to grind or you expect fatigue after 1602 m of climbing, step up to 34×34 for extra insurance on that 23.69% wall. There is no downside to a bigger cog on a climb this long — the flatter kilometres let you spin comfortably regardless.

Summary

Puerto de los Pilones rewards the patient endurance rider: 39.9 km of climbing where a low average masks genuinely severe pitches. Pace the flats, gear for the walls, and let the length do the work of testing you.

Length: 39.9 km
Average gradient: 4.01%
Max gradient: 23.69%
Start: 145 m
Summit: 1747 m
Net gain: 1602 m
Total ascent: 1716 m
Category: 1