Alto de la Raya

Overview

Alto de la Raya is a hors catégorie climb that earns its rating without any statistical trickery. Over 19.2 km the road lifts you from a start elevation of 698 m to a summit of 2670 m, a net gain of 1972 m. The average gradient is 10.27% — and that is a genuine, sustained average across nearly twenty kilometers, not a figure inflated by one savage ramp. Climbs that hold double-digit percentages for this long are rare, and they demand a completely different mindset than a punchy 10-minute effort.

The total ascent registers 2118 m, slightly more than the net gain of 1972 m. That difference of 146 m tells you there are small dips and flatter kickers folded into the ascent, but do not expect meaningful recovery — on a climb averaging 10.27%, even the "easier" sections rarely dip far below where they can hurt you.

How the Gradient Unfolds

Think of this climb as an unbroken wall rather than a series of distinct pitches. With a 10.27% average sustained over 19.2 km, the defining feature is relentlessness: the gradient gives you nowhere to hide and no long false-flats to spin out your legs. The 146 m gap between total ascent (2118 m) and net gain (1972 m) hints at a handful of brief settling points, but they arrive too infrequently to reset your legs.

Because the summit sits at 2670 m, the upper reaches also introduce thinning air. As you climb toward that altitude, the same power produces less speed, and your perceived effort creeps upward independently of the gradient. Plan for the top third to feel harder than the numbers alone suggest.

Pacing Notes

On a climb this long and this steep, pacing is everything. Anchor your effort to your FTP rather than to speed or ego. For a sustained 19.2 km effort, most riders should target a percentage of FTP they can genuinely hold for the full duration — the mistake here is starting hot and detonating halfway up a wall you cannot coast down.

If you are unsure of your threshold, run the numbers through the FTP estimator before you commit to the climb. Knowing your ceiling turns a 10.27% average from a guessing game into a manageable, repeatable power target. Ride the first several kilometers a touch conservatively; the altitude near the 2670 m summit will collect any debt you accumulate early.

Gearing

Do not under-gear this one. A 10.27% average over 19.2 km punishes anyone forced to grind a big cog at low cadence. A compact 34-tooth inner chainring is the sensible starting point, and it should be paired with a wide-range cassette.

A 34×32 is the bare minimum for strong climbers who can hold torque at altitude. For most riders, 34×34 is the smarter choice, giving you the extra spin to protect your knees and keep cadence alive deep into the effort. If your setup allows an even easier low gear, you will not regret it near the top.

Summary

Alto de la Raya is a pure test of sustained climbing: long, unbroken, and unforgiving from bottom to top. Pace it by power, gear it low, and respect the altitude.

Length: 19.2 km
Average gradient: 10.27%
Max gradient: n/a
Start: 698 m
Summit: 2670 m
Net gain: 1972 m
Total ascent: 2118 m
Category: HC