Passo della Vacca

Overview

Passo della Vacca is one of the hardest climbs you can point a bike at. Over 19.6 km it averages a brutal 9.83%, hauling you from a valley floor at 428 m all the way to a summit at 2355 m. That is 1927 m of net elevation gain, with 2007 m of total ascent once the few brief respites are accounted for. Rated HC — hors catégorie, the top of the scale above categories 1 through 4 — this is a climb that offers no easy way up. Nearly 20 km of near-double-digit average gradient is the kind of number most riders will remember for the rest of the season.

How the Gradient Unfolds

The headline figure is that 9.83% average, but averages hide the story. With a maximum pitch of 24.59%, there are ramps here that are less about riding and more about surviving. The gap between the 9.83% average and the 24.59% max tells you the climb is uneven: long stretches sit at or above the average, punctuated by savage kicks that spike toward a quarter-grade wall. Because total ascent (2007 m) sits above net gain (1927 m), there are small dips or flatter shelves along the way — but those 80 m of give-back cost you extra climbing later. Expect to be constantly resetting your rhythm rather than settling into one gear.

Pacing Notes

On a climb this long and steep, pacing is everything. Nineteen-plus kilometres at 9.83% will punish anyone who goes out hot, so anchor your effort to your sustainable power. A good target is riding just under or right at your FTP for the shallower sections, and accepting brief surges above it only where the gradient forces your hand near those 24.59% ramps. If you do not know your threshold, run the numbers through the FTP estimator before you commit to a plan. With over 1900 m of vertical to gain, the summit at 2355 m arrives slowly — meter it out and keep something in reserve for the steepest pitches, because there is no coasting to recover on a slope this relentless.

Gearing

Do not under-gear this one. For most riders a compact 34-tooth chainring paired with a wide cassette is the minimum. A 34×32 is a sensible baseline for strong climbers, but given sustained 9.83% gradients and pitches to 24.59%, a 34×34 — or an even easier one-by or gravel-style ratio — will save your legs and your cadence when the road tilts skyward. The extra range is not a luxury on a 19.6 km HC climb with 1927 m of gain; it is what keeps you spinning rather than grinding to a halt.

Summary

Passo della Vacca is a benchmark HC effort: long, steep, and unforgiving from the 428 m base to the 2355 m top. Come with low gears, a disciplined pacing plan, and respect for the numbers.

Length: 19.6 km
Average gradient: 9.83%
Max gradient: 24.59%
Start: 428 m
Summit: 2355 m
Net gain: 1927 m
Total ascent: 2007 m
Category: HC