Alto de San Rafael

Overview

Alto de San Rafael is not a climb you ease into — it is one you survive. Over just 6.9 km it averages a savage 13.87%, a figure that would be the maximum gradient on many respectable climbs. This is hors catégorie (HC) terrain, the top rung of the difficulty ladder above categories 1 through 4, and the numbers explain why. You start at 915 m and finish at 1866 m, a net gain of 951 m packed into under seven kilometers. There is no runway, no gentle valley approach to spin the legs loose. The road tilts up and stays up.

How the Gradient Unfolds

The defining truth of San Rafael is that its average and its difficulty are the same story. At 13.87% mean gradient, there are effectively no recovery sections — the climb is relentlessly steep from bottom to top. The pitch peaks at 20.06%, a wall-like ramp that will have you out of the saddle and clawing for traction. With total ascent recorded at 906 m against a net gain of 951 m, the profile is almost purely upward: what little variation exists comes from the gradient swinging between merely hard and outright brutal, not from any genuine descent. Treat every meter as climbing meters. The summit at 1866 m is the only relief on offer.

Pacing Notes

On a climb this steep and this short, pacing is everything — go too hard on the opening ramps and the 20.06% sections near the top will break you. Your FTP is the number to anchor to here. Because the gradient rarely dips, you will likely spend the entire ascent at or above threshold, so knowing that ceiling precisely matters. If you are not sure of yours, run the numbers through the FTP estimator before you commit to a pacing plan. Aim to hold a steady, sustainable effort through the first kilometers and keep a small reserve for the steepest pitch. On a 6.9 km wall averaging 13.87%, discipline beats bravado every time.

Gearing

Do not under-gear this one. A compact 34-tooth chainring is the starting point, but the cassette is where San Rafael is won or lost. A 34×32 is the bare minimum for most riders, and even then you will be grinding through the 20.06% ramps at a low cadence. If your knees or your fitness prefer to spin, go bigger: a 34×34 gives you meaningfully more room to keep the pedals turning on the steepest sections. For anyone who does not race up 13.87% averages weekly, the 34×34 is the smarter, safer choice. When in doubt on an HC climb this steep, the easier gear is always the right call.

Summary

Alto de San Rafael is a short, uncompromising HC climb that trades length for sheer severity. Bring low gearing, a paced effort, and respect for the 20.06% ramps, and the 1866 m summit is yours.

Length: 6.9 km
Average gradient: 13.87%
Max gradient: 20.06%
Start: 915 m
Summit: 1866 m
Net gain: 951 m
Total ascent: 906 m
Category: HC