Puerto de las Erillas

Overview

Puerto de las Erillas is a category 2 climb in Spain that runs 8.4 km from base to summit. It gains 437 m of net elevation, starting at 1,219 m and topping out at 1,656 m. That places the whole effort at altitude, where thinner air quietly taxes your legs on top of the gradient itself.

The headline number to watch is the gap between net gain and total ascent. You climb 437 m on paper, but the road actually racks up 572 m of ascent along the way. That 135 m difference means the profile is not a clean, one-way ramp — it undulates, giving back elevation you then have to re-earn. Every metre lost to a dip or false flat is a metre you pay for twice, so the perceived effort runs higher than a flat 5.18% average would suggest.

How the Gradient Unfolds

The 5.18% average is a blend, not a constant. With 135 m of re-climbing folded in, stretches of the road sit well below average — and to keep the average intact, other stretches must sit well above it. The 10.11% maximum gradient marks the sharpest of those, roughly double the mean, and it is where riders who paced off the average number get caught out.

Expect the profile to break down roughly like this:

• Flatter or recovery sections where the road eases off and even dips, letting you spin and eat
• Repeated short climbs that give elevation back after each dip, forcing you to re-accelerate
• A steepest ramp near 10.11% that demands a gear in reserve and a controlled, seated tempo

Pacing Notes

On an undulating climb like this, chasing an even speed is a trap. Holding constant km/h means spiking your power on every steep pitch and coasting on the flatter bits — you burn matches you cannot get back. Aim instead for even effort: hold a steady, sustainable power output and let your speed rise and fall with the terrain.

Practically, ease slightly into the dips and false flats, then meter your effort back up as the 10.11% sections arrive rather than lunging at them. If you do not know your ceiling, run the FTP estimator first and set a target you can hold for the full 8.4 km, not just the opening slopes.

Gearing

The 10.11% maximum gradient governs your setup. At that pitch, a standard chainset leaves you grinding, especially at 1,656 m of altitude. Fit a compact or sub-compact chainset paired with a wide-range cassette — a 34×32 or 34×34 gives you a bailout gear for the steepest ramp and keeps your cadence up through the repeated short climbs. Check your setup before the ride; discovering you are over-geared halfway up a Cat-2 is not the place to find out.

Summary

• Length: 8.4 km
• Average gradient: 5.18%
• Maximum gradient: 10.11%
• Net elevation gain: 437 m
• Total ascent: 572 m
• Category: 2

Puerto de las Erillas rewards riders who respect its undulation over its average. Pace by effort, gear for the 10.11% ramp, and treat the 135 m of hidden re-climbing as the real challenge — not the 5.18% on the sign.