Alto de Curies

Overview

Alto de Curies is a 7.9 km category-2 climb that gains 416 m from base to summit, running from 2487 m up to a lofty 2903 m. Its average gradient of 5.26% reads gentle on paper, but two details reshape that impression: a max pitch of 12.27% that more than doubles the mean, and a summit sitting near 2903 m where the air is noticeably thin. Category 2 places it in the middle of the difficulty ladder — well short of the hors-catégorie monsters, but demanding enough that you will feel every one of those 416 vertical metres by the top.

The total ascent of 408 m sits just below the net gain of 416 m, which tells you this is an almost relentlessly upward road with little in the way of descending relief. What you climb, you keep.

How the Gradient Unfolds

At 5.26% average across 7.9 km, Curies is a steady grinder rather than a wall. But the 12.27% max gradient — more than twice the average — means the difficulty is not evenly spread. Expect the road to hover around the mid-single-digit percentages for long stretches, punctuated by a ramp that stings past 12%. Because the total ascent (408 m) is so close to the net gain (416 m), there are essentially no false flats or downhill breathers to recover on; the elevation profile climbs and stays climbing.

The real multiplier here is altitude. Starting at 2487 m and topping out at 2903 m, every effort costs more oxygen than the same wattage would at sea level. A gradient that feels manageable low down becomes genuinely taxing as you approach the summit.

Pacing Notes

Ride Curies to its average, not to its steepest ramp. At 5.26% over 7.9 km, this is a tempo-to-threshold effort for most riders, so anchor your pacing to your FTP and hold something in reserve for the 12.27% pitch. If you do not know your threshold number, run your recent numbers through the FTP estimator before you commit to a target.

The altitude changes the maths. Above 2487 m, and especially nearing 2903 m, your sustainable power drops, so a wattage that feels easy at the base can tip you over the edge near the top. Start a notch below what the 5.26% average suggests, and let the summit come to you.

Gearing

For a 7.9 km climb averaging 5.26% with a 12.27% spike — at altitude — give yourself room to spin. A compact 34-tooth chainring paired with a 34×32 low gear covers most riders comfortably on the sustained sections. If you climb light, tire early on long efforts, or want insurance for that 12.27% ramp when your legs are already deep into 416 m of gain, step up to a 34×34. The thin air near 2903 m rewards a higher cadence, and the extra sprocket keeps you turning instead of grinding.

Summary

Alto de Curies is a steady category-2 climb whose real challenge is altitude and a single sharp ramp rather than sustained steepness. Pace to the 5.26% average, gear for the 12.27% max, and respect the thin air above 2487 m.

Length: 7.9 km
Average gradient: 5.26%
Max gradient: 12.27%
Start: 2487 m
Summit: 2903 m
Net gain: 416 m
Total ascent: 408 m
Category: 2