Alto de Témpanos

Overview

Alto de Témpanos is a hors catégorie monster, the kind of climb that redefines what your legs think they can do. Over 33.7 km it lifts you from 2034 m to 3897 m, a net gain of 1863 m stacked into a single, uninterrupted effort. The headline average of 5.53% sounds almost civilised, but that number hides both the true scale of the day and the punishing pitches buried inside it. This is a full HC ascent measured in hours, not minutes, ridden entirely at altitude where thin air taxes every watt you produce.

How the Gradient Unfolds

Do not be fooled by the 5.53% average. Because the total ascent of 2115 m exceeds the net gain of 1863 m, there are false flats and short reprieves along the way where the road eases or briefly kicks back downhill before climbing again. That extra 252 m of ascent tells you the profile is lumpy rather than metronomic. The sting is the 18.38% maximum gradient — a wall more than three times steeper than the average, the kind of ramp that forces you out of the saddle and empties the tank if you meet it carrying too much speed or too little patience. Expect long steady drags punctuated by sharp, leg-breaking spikes.

Pacing Notes

On a climb this long, pacing is everything. Ride the first third well within yourself; the summit at 3897 m is a long way off and the altitude compounds every mistake. Anchor your effort to your FTP and aim to sit comfortably below threshold on the sustained sections, saving headroom for the 18.38% pitches where power naturally spikes. If you do not know your threshold, run the numbers through the FTP estimator before you commit to a target. The golden rule: never chase the steep ramps at full gas — soft-pedal the brief flatter sections to recover, then meter your climbing so you still have something left when the road tilts up hard near the top.

Gearing

Gear for survival, not ego. With 33.7 km at altitude and ramps hitting 18.38%, you want the widest range you can bolt on. A compact 34-tooth chainring paired with a 34×32 low is a sensible minimum, but on a climb of this length and steepness a 34×34 buys you precious extra cadence and spares your knees over 1863 m of ascending. Riders who spin rather than grind will fare far better here — the ability to keep the pedals turning through the 18.38% sections is worth more than any aero advantage. If your bike will take it, err toward the easier 34×34.

Summary

Alto de Témpanos is a genuine HC test: 33.7 km of climbing, 1863 m of net gain, a summit at 3897 m, and a maximum gradient of 18.38% waiting to catch anyone who paces it poorly. Ride it patiently, gear it generously, and respect the altitude.

Length: 33.7 km
Average gradient: 5.53%
Max gradient: 18.38%
Start: 2034 m
Summit: 3897 m
Net gain: 1863 m
Total ascent: 2115 m
Category: HC