Passo della Porretta

Overview

Passo della Porretta is a category 1 ascent that stretches 15.6 km from a valley floor at 109 m up to a summit of 940 m. That works out to 831 m of net elevation gain, with a total ascent of 807 m once the small false-flats and dips along the way are accounted for. The headline number is an average gradient of 5.33%, which reads as moderate on paper — but the climb hides a maximum pitch of 15.03%, nearly three times the average. This is a long, sustained effort where the danger lies not in any single wall but in the accumulation of vertical meters over the better part of an hour for most riders.

How the Gradient Unfolds

An average of 5.33% across 15.6 km tells you this is a rhythm climb, not a punchy one. But averages smooth over the texture. With a max of 15.03%, the road clearly throws steeper sections into the mix, meaning the shallower stretches must sit well below the 5.33% mean to balance the ledger. Expect the profile to breathe: kilometers where you spin comfortably, punctuated by ramps that briefly triple the gradient before easing again. The gap between 807 m of total ascent and 831 m of net gain is small — only 24 m — which tells you there are very few descents or flat recovery zones. The road climbs almost the entire way, so momentum management matters more than surviving isolated spikes.

Pacing Notes

On a climb this long, pacing discipline is everything. Anchor your effort to your FTP and resist the urge to chase the steep ramps out of the saddle — the 15.03% pitches will spike your power far above threshold and leave you paying for it across the remaining kilometers. Aim to hold a steady, sustainable output on the 5.33% sections and only briefly lift the effort over the steepest ramps, settling back down as soon as the gradient relents. If you don't know your threshold number, run it through the FTP estimator before your attempt so you can set a realistic target for a sustained 15.6 km. Fueling and hydration are non-negotiable on an effort of this duration.

Gearing

Given the length and that 15.03% maximum, gear for the steep ramps rather than the average. A compact 34-tooth inner ring paired with at least a 32-tooth cassette sprocket — a 34×32 — is a sensible baseline for most riders on this category 1 climb. If you value your knees, ride at a lighter body weight-to-power ratio, or simply prefer to spin, step up to a 34×34. The extra range costs you nothing on the shallower 5.33% stretches and buys real insurance when the road kicks toward 15.03% late in the effort, when fatigue makes every extra tooth count.

Summary

Passo della Porretta rewards patience: a long, mostly relentless drag with just enough gradient variation to punish riders who go out too hard. Pace it by threshold, gear it for the steep ramps, and let the 15.6 km come to you.

Length: 15.6 km
Average gradient: 5.33%
Max gradient: 15.03%
Start: 109 m
Summit: 940 m
Net gain: 831 m
Total ascent: 807 m
Category: 1