Passo Siera

Overview

Passo Siera is a proper category-1 test: 16.8 km of continuous climbing that lifts you from a valley floor at 501 m up to a summit of 1598 m. That is a net elevation gain of 1097 m, delivered at an average gradient of 6.53%. On paper the average reads as steady tempo work, but averages flatten the truth — buried inside the climb is a maximum pitch of 31.02%, a wall steep enough to reduce a strong rider to a crawl. The total ascent of 1061 m confirms this is an almost relentlessly upward road, with only fractional respite along the way.

How the Gradient Unfolds

The gap between the 6.53% average and the 31.02% maximum is the whole story here. A climb that never strayed far from its average would be a rhythm effort you could ride on feel. Passo Siera is not that climb. Expect long stretches near or slightly above 6.53%, punctuated by sharp ramps that spike far harder. The near-perfect match between net gain (1097 m) and total ascent (1061 m) tells you the road rarely gives anything back — there are almost no descents to recover on. You climb, then you climb some more, and every metre of altitude is earned. Ride the shallower sections controlled so you have reserves for the ramps, because the steepest pitches arrive without warning and punish anyone already deep in the red.

Pacing Notes

Over 16.8 km, pacing discipline decides your day. Anchor your effort to your FTP: on the sustained 6.53% grades, aim to sit just below threshold so you can absorb the surges without blowing apart. When the gradient rockets toward 31.02%, you will unavoidably go over threshold for short bursts — accept that, but keep those spikes brief and settle back down the moment the road eases. The single biggest mistake on a climb like this is starting too hot on the lower slopes and having nothing left when the wall hits. If you are unsure where your threshold sits, run the numbers through the FTP estimator before you commit to a target, and build your pacing plan around a power you can genuinely hold for the full 16.8 km.

Gearing

Do not under-gear this one. The 6.53% average is manageable with a compact setup, but the 31.02% maximum demands a bailout gear. A 34×32 is the sensible floor for most riders on Passo Siera, giving you a low enough ratio to keep the pedals turning through the steep pitches without grinding to a stall. If you carry any fatigue, ride at a heavier body weight, or simply want to spin rather than muscle the ramps, step down to a 34×34. That extra sprocket is cheap insurance across a climb this long, where preserving cadence on the walls keeps your effort aerobic instead of forcing repeated all-out surges that drain you before the summit.

Summary

Passo Siera earns its category-1 status honestly: long, sustained, and spiked with a genuinely brutal maximum ramp. Pace it below threshold, gear it low, and respect the walls. Do that, and the summit at 1598 m is a reward rather than a reckoning.

Length: 16.8 km
Average gradient: 6.53%
Max gradient: 31.02%
Start: 501 m
Summit: 1598 m
Net gain: 1097 m
Total ascent: 1061 m
Category: 1