Alto del Rey

Overview

Alto del Rey is a category 1 climb that asks a real question of your legs over 12.9 km. From a start elevation of 946 m it lifts you to a summit of 1775 m, a net gain of 829 m across a road that averages 6.41%. The total ascent registers at 821 m, so what you see is very close to what you climb — this is a climb that goes up and largely stays up, with little in the way of false flat or recovery descent to break the rhythm.

At just under 13 km, it sits firmly in the range where pacing matters more than punch. The category 1 rating (one step below the fearsome HC) tells you this is a serious effort, but not an unrelenting wall. The 6.41% average is honest and sustained, and the 14.89% max gradient is the sting hidden inside an otherwise steady profile.

How the Gradient Unfolds

The headline numbers describe a climb of two personalities. The 6.41% average is a gradient most trained climbers can hold for a long time, but the 14.89% maximum is more than double that — a spike that will force you out of the saddle or deep into your easiest gear.

With a net gain of 829 m and total ascent of 821 m over 12.9 km, the road climbs relentlessly. The small gap between net gain and total ascent means there is almost no respite: no plunging switchbacks that give the legs a breather, just a continuous grind from 946 m to 1775 m. Expect the gradient to hover around the average through the bulk of the climb, then rear up toward that 14.89% pitch on the steepest ramp. Ride the steady sections conservatively so you have something left when the road bites.

Pacing Notes

The key to Alto del Rey is treating the 6.41% average as your baseline and the 14.89% ramp as the moment you protect. A climb of this length rewards a power ceiling anchored to your FTP — settle in a shade below threshold on the steady gradient and you can hold it across all 12.9 km without blowing up.

If you do not know your threshold, use the FTP estimator to set a realistic target before you commit to the lower slopes. Bank a little reserve for the steepest pitch: hitting 14.89% with nothing left turns a hard climb into a walk. Aim to crest at 1775 m feeling like you emptied the tank in the final kilometers, not the first.

Gearing

For 12.9 km at 6.41% average with ramps to 14.89%, err generous on gearing. A compact 34-tooth chainring paired with a wide cassette is the sensible baseline. A 34×32 will get most fit riders over the steady sections, but the 14.89% max is exactly where a bigger sprocket earns its keep — a 34×34 gives you the extra range to spin rather than grind through the steepest ramp and protect your legs for the summit. If your bike can take it, the 34×34 is the safer choice for a climb this long.

Summary

Alto del Rey is a sustained category 1 climb: 12.9 km, 829 m of net elevation gain, and a 6.41% average with a 14.89% sting. Pace it to your threshold, gear generously, and respect the fact that it climbs almost every meter of the way from 946 m to 1775 m.

Length: 12.9 km
Average gradient: 6.41%
Max gradient: 14.89%
Start: 946 m
Summit: 1775 m
Net gain: 829 m
Total ascent: 821 m
Category: 1