Selletta dei Castelloni

Overview

Selletta dei Castelloni is an HC climb, and the numbers explain why without any embellishment. It runs 11.1 km from a start elevation of 251 m to a summit at 1711 m, and the average gradient is a brutal 13.21%. That is not a rolling road with a few steep ramps — it is a sustained double-digit wall for the better part of an hour. The net elevation gain is 1460 m, while the recorded total ascent of 1386 m tells you almost every metre of that climbing goes one direction: up. With HC being the hardest category — above 1, 2, 3 and 4 — this is a climb you plan for, not one you stumble onto.

How the Gradient Unfolds

At 13.21% average over 11.1 km, there is nowhere to hide. If the road held that exact figure the whole way it would still be one of the steepest sustained climbs you can ride, and the small gap between the 1460 m net gain and the 1386 m total ascent means there are effectively no downhill or flat sections to recover on. Treat the entire 11.1 km as one continuous effort. The difference between 251 m at the base and 1711 m at the top is 1460 m of pure vertical, gained relentlessly. Expect the pitch to bite from the first pedal strokes and to keep biting until the summit.

Pacing Notes

On a climb this steep, pacing is survival. Your goal is to hold a steady, sustainable power just under threshold and never let a surge blow you apart, because at 13.21% there is no coasting back to recovery. Anchor your effort to your FTP and ride the lower slopes conservatively — the climb is long enough at 11.1 km that going into the red early will cost you dearly over 1460 m of gain. If you are unsure of your threshold number, run the FTP estimator before you attempt this, then target a wattage you know you can hold for the full duration.

Gearing

Gear for the average, not the ideal. At a 13.21% mean gradient sustained across 11.1 km, most riders will want the lowest ratio they can get. A compact 34-tooth chainring paired with a wide cassette is the sensible starting point: a 34×32 will work for strong climbers with good legs, but on a wall this steep a 34×34 gives you the extra margin to spin rather than grind, protecting your knees and keeping cadence up over 1460 m of climbing. If your setup allows anything lower than 34×34, use it — nobody has ever regretted an easier gear on an HC ascent.

Summary

Selletta dei Castelloni is a pure HC test: 11.1 km that never relents, averaging 13.21% and lifting you 1460 m to a 1711 m summit. Come with low gearing, a disciplined pacing plan, and respect for the numbers.

Length: 11.1 km
Average gradient: 13.21%
Max gradient: n/a
Start: 251 m
Summit: 1711 m
Net gain: 1460 m
Total ascent: 1386 m
Category: HC