Puerto de Casillas

Overview

Puerto de Casillas is a Category 1 climb in Spain, running 11 km from a base at 623 m to a summit at 1467 m. That gives a net elevation gain of 844 m over the ascent, at an average gradient of 7.68%. It is a serious, sustained effort: long enough to demand pacing discipline, steep enough on average to keep you out of any comfortable rhythm for extended stretches.

The headline number to watch is the gap between net gain and total ascent. While you climb 844 m net, the road actually accumulates 1043 m of ascent — meaning roughly 199 m of the elevation you gain is given back and re-earned along the way. That undulation matters: it tells you the climb is not a single unbroken grade but a rolling profile with dips and re-ascents. Every metre of descent is a metre you have to climb twice, and those transitions break your cadence and cost matches you might rather save for the top.

How the Gradient Unfolds

The 7.68% average is a blend, not a constant. With 199 m of "wasted" ascent baked into the profile, the real climbing sections must be steeper than the average implies to compensate for the flatter and descending parts. Expect the gradient to swing well above and below that mean.

• Flatter or false-flat sections where the road eases and briefly lets you recover
• Short descents or dips that interrupt your rhythm and force a re-climb
• Repeated pitches that stack up rather than one smooth grade
• A steepest ramp hitting 19.4% — a wall that demands you already be in your easiest gear

Pacing Notes

On an undulating climb like this, even-effort beats even-speed. Chasing a constant speed forces you to surge on the steep ramps and coast on the flats, spiking your power exactly when it hurts most. Instead, anchor your pacing to a sustainable power output and hold it steady across the whole 11 km — let your speed rise on the shallow sections and fall on the walls while your effort stays flat.

The recovery dips are a gift: soft-pedal them rather than filling them with power. If you do not know your target number, run the FTP estimator before you ride and set a ceiling you can defend all the way to 1467 m.

Gearing

The 19.4% maximum gradient governs your setup, not the average. Gearing for 7.68% will leave you grinding and out of the saddle when the road kicks to nearly 20%. Run a compact or sub-compact chainset paired with a wide-range cassette — a 34×32 or 34×34 gives you the low end to spin the steepest ramp at a survivable cadence. Check your drivetrain before the ride; discovering you are over-geared halfway up a Category 1 climb is not a mistake you recover from.

Summary

• Length: 11 km
• Average gradient: 7.68%
• Maximum gradient: 19.4%
• Net elevation gain: 844 m
• Total ascent: 1043 m
• Category: 1

Puerto de Casillas rewards riders who respect the profile. Pace to effort, gear for the 19.4% wall, and treat the undulation as the real challenge — the average never tells the whole story.