Alto de la Viga

Overview

Alto de la Viga is a hors catégorie monster: 28.7 km of continuous climbing that lifts you from 1725 m at the base to a summit at 3661 m. The average gradient of 6.74% sounds civilized on paper, but the raw arithmetic tells the real story. This is a climb that gains 1936 m of net elevation and racks up 2019 m of total ascent across its length. That gap between net gain and total ascent means the road does not simply point up and stay there — there is enough rolling and re-climbing to add roughly 83 m of extra vertical you have to pay for twice.

Add the altitude itself, topping out well above 3600 m, and you have a climb that punishes both legs and lungs. Every watt costs more up here than it would at sea level.

How the Gradient Unfolds

The 6.74% average is a blend, not a constant. With a max gradient of 21.5%, there is at least one section more than three times steeper than the mean — a wall that will force you out of the saddle or into your easiest gear whether you planned to or not. Because the total ascent (2019 m) exceeds the net gain (1936 m), expect false flats and short descents scattered through the 28.7 km. Those are not rest — they are traps that break your rhythm and hand back elevation you then have to re-earn.

Read the climb in thirds: settle in early, protect your legs through the steepest ramps in the middle, and save something for the thin air near the 3661 m summit.

Pacing Notes

Over 28.7 km, pacing is everything. This is a threshold effort measured in hours, not minutes, so anchor your climb to your FTP rather than to how you feel on the first kilometre. On a climb this long, going even a few percent too hard early compounds badly by the top.

A sane target is a steady sub-threshold effort, backing off further on the 21.5% pitches so you do not spike into the red and blow apart your rhythm. If you do not know your number, run it through the FTP estimator before you commit to a plan. Then subtract a little for the altitude — the summit sits high enough that your usable power drops noticeably above 3000 m.

Gearing

Do not under-gear this one. With a 21.5% max gradient stacked on top of nearly 29 km of climbing, mechanical advantage matters more than pride. A compact 34-tooth chainring is the starting point. Pair it with at least a 34×32 for the merely steep sections, but for the 21.5% ramps at altitude, a 34×34 will keep your cadence turning instead of grinding you to a stall. If your frame and derailleur can take an even larger cassette, take it — spinning a low gear beats muscling a high one for 1936 m of gain.

Summary

Alto de la Viga is a full HC test: long, high, and genuinely steep in the wrong places. Respect the distance, gear low, pace to your threshold, and treat the altitude as a tax on every effort. Get those right and the 3661 m summit is yours.

Length: 28.7 km
Average gradient: 6.74%
Max gradient: 21.5%
Start: 1725 m
Summit: 3661 m
Net gain: 1936 m
Total ascent: 2019 m
Category: HC