Alto de Ventanas

Overview

Alto de Ventanas is an hors catégorie beast, the kind of climb that redraws your sense of what "long" means. Over 31.6 km the road lifts you from a start elevation of 115 m to a summit at 2022 m — a net gain of 1907 m. The average gradient reads 6.03%, which sounds humane until you remember it holds that pitch for more than thirty kilometres. This is not a wall you sprint; it is a distance you survive. With a max gradient of 10.16%, the steepest ramps are sharp but never truly savage — the difficulty here is duration, not any single cruel pitch.

How the Gradient Unfolds

The number that governs this climb is 6.03%, and the story of Ventanas is how consistently that figure asserts itself. Total ascent comes in at 1852 m against a net gain of 1907 m, and the gap between those two figures — just 55 m — tells you almost everything: there is barely any descending or false-flat relief across the whole 31.6 km. What goes up, stays up. The road climbs, and climbs, and keeps climbing.

The 10.16% max gradient marks the hardest ramps, roughly 4 percentage points above the average. Expect the pitch to breathe between the high 4% range and low double digits, forcing you to keep resetting your rhythm. On a climb this long, those swings are the real test — every steep section is a small withdrawal from a bank account you must make last nearly two vertical kilometres.

Pacing Notes

Discipline wins here. On a 31.6 km effort, going into the red early is the classic mistake — the summit at 2022 m is a long way from the 115 m start, and there is no coasting to recover. Anchor your effort to your FTP and hold something in reserve for the upper slopes, where altitude thins the air. If you don't know your threshold, run the numbers through the FTP estimator before you commit.

Aim to sit just below threshold on the average 6.03% grade and let the 10.16% ramps briefly lift you above it, then settle back down. Over 1907 m of net climbing, small overspends compound into a blow-up. Ride the climb, don't attack it.

Gearing

For an HC climb of this length, gear low and thank yourself later. A compact 34-tooth chainring paired with a wide cassette is the sensible baseline. A 34×32 will get most fit riders up the steady 6.03% stretches, but on the 10.16% ramps late in a 31.6 km grind — with tired legs — a 34×34 gives you the extra spin to protect your knees and hold cadence. If your bike can take it, size down; nobody has ever regretted an easier gear near 2022 m.

Summary

Alto de Ventanas is an endurance climb in the purest sense: not steep enough to break you in one blow, but long enough — 31.6 km, 1907 m of net gain — to grind down anyone who paces it wrong. Respect the distance, gear low, and ration your effort from the 115 m start to the 2022 m summit.

Length: 31.6 km
Average gradient: 6.03%
Max gradient: 10.16%
Start: 115 m
Summit: 2022 m
Net gain: 1907 m
Total ascent: 1852 m
Category: HC