Forcella Ziolera

Overview

Forcella Ziolera is an HC climb — hors catégorie, the hardest rating there is — and it earns the label without any padding. Over 13.7 km it averages 9.17%, a figure that would be brutal on a 5 km wall and is genuinely rare across a distance this long. You start at 807 m and finish at 2066 m, a net gain of 1259 m, with 1244 m of total ascent packed into a road that rarely lets you coast. There is no warm-up flat to hide behind and no false summit to reward you early. This is a sustained, high-altitude effort where the average gradient is close enough to the max that the whole climb feels like one long ramp.

How the Gradient Unfolds

The defining feature here is the gap between the 9.17% average and the 20.56% maximum. That spread is only about 11.4%, which tells you the road is remarkably consistent — the steepest pitches are not wild outliers, they are the same terrain turned up a notch. Expect long stretches hovering right around the average, punctuated by ramps that lurch toward 20% and force a sharp change of cadence. Because the net gain of 1259 m nearly matches the 1244 m of total ascent, there is almost no descending built in: virtually every metre you climb, you keep. Over 13.7 km that consistency is a double-edged sword. It is predictable, but it never gives your legs the micro-recoveries that rolling climbs offer.

Pacing Notes

On a climb this uniform, pacing is everything. The 9.17% average means power output is the single lever that decides whether you finish strong or blow apart at altitude. Anchor your effort to your FTP: on a sustained HC effort lasting well over an hour, most riders want to sit just below threshold and hold it there, treating the 20% ramps as brief accelerations rather than new baselines. If you overcook the lower slopes, the thin air near 2066 m will find you out. Not sure where your threshold sits? Run the numbers through the FTP estimator before you go, then translate that into a target you can hold for the full 13.7 km. The riders who pace it well are the ones who look almost bored on the lower half.

Gearing

Do not under-gear this one. With a 9.17% average and pitches to 20.56%, a compact crankset paired with a wide-range cassette is the sensible floor. A 34×32 will get most fit climbers up the sustained sections, but the 20% ramps late in the climb — after you have already gained more than a thousand metres — are where a 34×32 starts to feel heavy. If your legs are anything short of race-fit, drop to a 34×34 for the extra cushion; the lower ratio lets you spin the steep pitches instead of grinding them, which matters enormously across 13.7 km of near-constant load.

Summary

Forcella Ziolera is a pure test of sustained climbing: long, steep, consistent, and finishing at real altitude. Pace it to your threshold, gear it generously, and respect the fact that the road almost never eases.

Length: 13.7 km
Average gradient: 9.17%
Max gradient: 20.56%
Start: 807 m
Summit: 2066 m
Net gain: 1259 m
Total ascent: 1244 m
Category: HC