Alto de la Mona

Overview

Alto de la Mona is a genuine hors catégorie monster, and the numbers tell you why before you ever turn a pedal. At 36.4 km long it is not a climb you attack; it is a climb you survive by dosing your effort across the better part of an hour and a half. The average gradient of 5.78% sounds almost civilised, but that figure is stretched over a colossal distance, and the summit sits at 2768 m — high enough that thinning air becomes a real factor near the top. From a start elevation of 666 m you gain 2102 m net, with the total ascent reaching 2191 m once the small dips and rolls along the way are counted. That gap between net gain and total ascent tells you the road is not a perfectly smooth ramp; it undulates, and those undulations add up.

How the Gradient Unfolds

An average of 5.78% across 36.4 km hides a lot of variation. With a max gradient of 14.69%, there are pitches here more than two and a half times steeper than the average, and on a climb this long the steep sections tend to arrive when you least want them. Because the total ascent of 2191 m exceeds the net gain of 2102 m, you will encounter brief respites and even short descents that force you to re-accelerate a loaded body up the next rise. Treat the climb as a series of blocks rather than one continuous wall. The high summit elevation of 2768 m means the final kilometres feel harder than the gradient alone suggests — altitude quietly taxes every watt.

Pacing Notes

On a climb of this magnitude, pacing is everything. Anchor your effort to your FTP and stay disciplined below it for the vast majority of the 36.4 km; going into the red early on a 2102 m ascent is a mistake you cannot claw back. Aim to hold a steady sub-threshold power on the sustained 5.78% sections, and only allow short surges over threshold on the steepest ramps toward that 14.69% max — then settle immediately afterward. If you are unsure of your number, run the FTP estimator before your attempt so your targets are grounded in real data. Above 2768 m of thin air, expect your sustainable power to sag, so bank a little in the bag for the top.

Gearing

Gear for survival, not heroics. A 36.4 km effort with pitches hitting 14.69% rewards a low, spinnable setup. A 34×32 is the sensible baseline for strong climbers who can hold a steady cadence, but given the 2191 m total ascent and the altitude at the 2768 m summit, most riders will be glad of a 34×34 to keep the legs turning when fatigue and gradient stack up together. The extra range costs you nothing on the shallow stretches and buys real insurance on the steep ones.

Summary

Alto de la Mona is a full-day objective: long, high, and unrelenting. Pace it by your FTP, gear low, and respect the altitude.

Length: 36.4 km
Average gradient: 5.78%
Max gradient: 14.69%
Start: 666 m
Summit: 2768 m
Net gain: 2102 m
Total ascent: 2191 m
Category: HC