Collado de la Gargantilla

Overview

The Collado de la Gargantilla is a category 1 climb that asks for genuine, sustained effort. Over 12.4 km it averages 6.1%, lifting you from a start elevation of 879 m to a summit at 1634 m. That is 755 m of net elevation gain, with a total ascent of 747 m once the small undulations along the way are counted. This is not a wall you sprint at and survive; it is a long, honest climb where the road just keeps tilting upward and rewards riders who ration their energy well.

How the Gradient Unfolds

A 6.1% average across 12.4 km sounds steady, but the road rarely sits exactly on that number. The gap between the 6.1% average and the 14.23% maximum tells you the story: there are ramps here that bite well above the mean, and easier stretches that let the average settle back down. Expect the climb to breathe — passages a touch below 6.1% where you can find rhythm, punctuated by steeper kicks that drag toward that 14.23% figure. Because the net gain (755 m) sits just above the total ascent (747 m), the profile is almost relentlessly upward, with very little descending to break the effort. Read every ramp as part of a longer accumulation rather than a one-off obstacle.

Pacing Notes

On a climb this length, pacing beats punch. Anchor your effort to your FTP: riding the bulk of the 12.4 km slightly under threshold keeps you from blowing up before the summit at 1634 m. When the road rears toward 14.23%, let your power drift up briefly, then settle back once the gradient eases below the 6.1% average — surging on every ramp burns matches you will want near the top. If you are unsure of your threshold, run the numbers through the FTP estimator before you plan your target. A conservative first half over the initial kilometres almost always yields a faster, more controlled second half across the remaining distance.

Gearing

With 755 m of climbing packed into 12.4 km and pitches reaching 14.23%, gearing is what keeps your cadence — and your legs — alive. For most riders, a compact 34-tooth chainring paired with a wide-range cassette is the sensible baseline. A 34×32 will handle the sustained 6.1% sections comfortably and give you enough range to spin through the steeper ramps. If you tend to grind, carry extra weight, or simply want to protect your legs late in the 12.4 km, step up to a 34×34 for a lower bailout gear on the harshest pitches near 14.23%. The taller the climb and the steeper the max, the more you will appreciate having that extra sprocket in reserve.

Summary

The Collado de la Gargantilla is a category 1 test of endurance and discipline: long, steadily uphill, and spiked with ramps that demand respect. Pace it to your threshold, gear low enough to keep spinning, and let the 755 m of gain come to you rather than chasing it.

Length: 12.4 km
Average gradient: 6.1%
Max gradient: 14.23%
Start: 879 m
Summit: 1634 m
Net gain: 755 m
Total ascent: 747 m
Category: 1