Flatschjoch - Passo Vallaccia

Overview

Flatschjoch - Passo Vallaccia is a hors catégorie effort that asks for everything you have and then a little more. Over 18.3 km the road lifts you from a start elevation of 977 m to a summit at 2389 m, a net gain of 1412 m and a total ascent of 1393 m once you account for the handful of dips along the way. The average gradient sits at a punishing 7.72%, and the steepest ramp bites at 20.84%. This is the kind of climb that earns its HC label honestly: long enough to hollow out your reserves, steep enough to keep you honest at every switchback.

How the Gradient Unfolds

The headline number, 7.72% averaged across 18.3 km, hides a rougher truth. A climb that gains 1412 m in net elevation but records 1393 m of total ascent tells you the road is not perfectly monotonic — there are brief moments of relief, but nothing you can call a rest. The 20.84% max gradient is nearly three times the average, so expect the profile to lurch well above 7.72% on its cruelest pitches. Treat the smoother stretches as recovery and the double-digit ramps as the real test. Save something for the upper reaches, because gradient rarely relents as you push toward 2389 m.

Pacing Notes

At 18.3 km and 7.72% average, this is a sustained tempo effort punctuated by anaerobic spikes. Anchor your pacing to a percentage of your FTP: riding just under threshold on the steady sections leaves headroom to absorb the 20.84% pitches without blowing apart. If you don't know your threshold power, run the numbers through the FTP estimator before you commit to a target. The single biggest mistake on a 1412 m climb is going out too hard in the first few kilometres — the summit at 2389 m is a long way off, and the steepest ramps are the ones that punish an early over-effort. Ride the average, respect the maximum.

Gearing

For an HC climb averaging 7.72% with ramps to 20.84%, gear low and gear early. A compact 34-tooth chainring paired with a 34×32 cassette gives most riders a workable floor for the steady 18.3 km grind. But on the 20.84% pitches, a 34×32 can leave you grinding at a cadence that shreds your legs — so if your derailleur allows it, run 34×34 for extra insurance. The marginal weight of a larger cassette is nothing next to the cost of stalling on a wall at 2389 m. When in doubt, take the easier ratio: spinning a low gear will always beat mashing a big one over 1412 m of climbing.

Summary

Flatschjoch - Passo Vallaccia is a full-value HC climb — long, steep, and unforgiving from 977 m to 2389 m. Pace it off your threshold, gear it low, and respect the 20.84% ramps, and you'll arrive at the top having earned every metre of the 1412 m gain.

Length: 18.3 km
Average gradient: 7.72%
Max gradient: 20.84%
Start: 977 m
Summit: 2389 m
Net gain: 1412 m
Total ascent: 1393 m
Category: HC