Passo del Fornetto

Overview

Passo del Fornetto is an HC ascent that asks for everything you have. Over 22.5 km the road rises from 242 m at the base to a summit of 2255 m, a net gain of 2013 m at an average gradient of 8.96%. That average alone would rank it among the hardest paved climbs anywhere, but the number that defines the day is the 33.29% maximum — a wall steep enough to threaten traction on a bad line. This is not a climb you ride into shape; it is one you arrive prepared for.

How the Gradient Unfolds

An 8.96% average sustained across 22.5 km leaves little room for genuine recovery. Because the total ascent of 1972 m sits just below the net gain of 2013 m, the road climbs almost relentlessly upward with barely any descending or flat to break the rhythm. The real story is variance: an average near 9% paired with a 33.29% spike means the pitches well above the mean are frequent and punishing. Expect long stretches that hover around the average, interrupted by ramps that jump into the high teens and twenties, with at least one section brushing that 33.29% ceiling. Ride the mellower gradients as your rest.

Pacing Notes

On a climb this long, pacing is survival. The 22.5 km distance means most riders will be climbing for well over an hour, so anchor your effort to a sustainable percentage of your FTP rather than chasing the steep ramps out of the saddle. Settle into a controlled tempo on the sections near the 8.96% average, then accept that the pitches toward 33.29% will briefly push you over threshold — spin them, don't grind them, and let your effort ease as the road relents. If you don't know your threshold, run the numbers first with the FTP estimator so your target wattage matches the 2013 m of vertical ahead of you.

Gearing

Gear for the steepest ramp, not the average. With a 33.29% maximum and a 22.5 km duration, most riders will want a compact crankset paired with a wide-range cassette. A 34×32 is the sensible floor here, but on a climb that gains 2013 m and spikes past 30%, a 34×34 gives you the extra margin to keep the pedals turning when the gradient bites. If your bike can accept an even larger sprocket, it is worth the swap. Preserving cadence on the walls protects your legs for the kilometres that follow, and on an HC climb of this length, running out of gears is running out of options.

Summary

Passo del Fornetto is a genuine hors catégorie test: 22.5 km, 8.96% average, and a 33.29% maximum, lifting you 2013 m from 242 m to 2255 m. Respect the distance, gear for the walls, and pace to your threshold — do that, and the summit is yours.

Length: 22.5 km
Average gradient: 8.96%
Max gradient: 33.29%
Start: 242 m
Summit: 2255 m
Net gain: 2013 m
Total ascent: 1972 m
Category: HC