Puerto de las Grajas

Overview

Puerto de las Grajas is a 16.1 km category 2 climb that starts almost at sea level, with the road beginning at just 7 m of elevation and topping out at 778 m. That leaves a net elevation gain of 771 m across the ascent, with a total ascent of 750 m once the small rolling dips along the way are accounted for. The average gradient of 4.78% sounds mild on paper, but a climb this long rarely lets you settle for good — and a max gradient of 17.17% guarantees at least one moment where the road bites hard.

How the Gradient Unfolds

The headline number is 4.78%, but that average hides the real texture. Over 16.1 km, the difference between the 750 m of total ascent and the 771 m net gain tells you the profile is not perfectly linear — there are brief levelling sections where the road eases before tilting up again. The defining feature is the max gradient of 17.17%, more than three times the average. Expect a steep ramp that spikes well above what your legs have been holding, then relents. Treat the climb as a long, mostly steady effort punctuated by a sharp pitch, not a uniform drag from bottom to top.

Pacing Notes

On a climb of 16.1 km, discipline beats bravado. Anchor your effort to your FTP and aim to sit just below threshold on the sustained sections, holding a rhythm you could defend for the full 771 m of climbing. If you do not know your threshold number, run the numbers through the FTP estimator before you set your target. The 17.17% ramp is where riders blow up — spin into it rather than muscling over, keep your effort a notch under redline as the grade rises, and recover on the flatter stretches. Banking a small buffer early pays off across all 16.1 km; overcooking the bottom leaves nothing for the summit at 778 m.

Gearing

With sustained kilometres at 4.78% and a spike to 17.17%, gear for the steep bits, not the average. A compact 34-tooth chainring paired with a wide-range cassette is the sensible baseline. A 34×32 will get most fit riders up the steady sections comfortably, but the 17.17% pitch is exactly where an extra sprocket earns its keep — a 34×34 gives you a lower bailout gear to keep your cadence up and your knees happy when the road kicks. If you have the range, fit the 34×34 and enjoy the insurance across the full 16.1 km.

Summary

Puerto de las Grajas rewards patience: a long, mostly steady 16.1 km climb with one genuinely steep ramp. Pace to threshold, gear low enough to spin the 17.17% section, and the 778 m summit comes to those who ride it smart.

Length: 16.1 km
Average gradient: 4.78%
Max gradient: 17.17%
Start: 7 m
Summit: 778 m
Net gain: 771 m
Total ascent: 750 m
Category: 2