Colle_della_Bicocca

Overview

Colle della Bicocca is a genuine hors catégorie test — 27.2 km of continuous climbing that earns its HC rating through sheer duration as much as steepness. From a start elevation of 722 m, the road grinds upward to a summit of 2286 m, delivering 1564 m of net elevation gain. Because the total ascent is 1671 m, there are small pitches of respite scattered through the climb, but not enough to change the character of the day: this is a long, sustained effort that rewards patience over aggression.

The headline average gradient of 5.74% sounds approachable, and on paper it is. But an average smooths over everything, and at 27.2 km in length, holding even a moderate slope for over an hour and a half is what breaks most riders — not the single steepest ramp.

How the Gradient Unfolds

The 5.74% average is the story only if you stop reading there. The maximum gradient hits 15.2%, nearly three times the mean, which tells you the climb is not evenly graded. Expect stretches that sit comfortably below the average, followed by sharp kicks that spike well into double digits.

The gap between the 1564 m net gain and the 1671 m total ascent — a difference of 107 m — confirms there are brief descents or false flats mixed in. Those small drops break rhythm and force you to re-accelerate, which costs more energy than the elevation numbers suggest. Treat every easing of the slope as recovery, not a chance to attack.

Pacing Notes

On a climb this long, pacing is everything. The single biggest mistake is chasing the early, gentler slopes and arriving at the 15.2% ramps already in the red. Anchor your effort to a target you can hold for the full 27.2 km, not for the first ten.

Set your ceiling using your FTP. Riding a sustained HC climb like this at a controlled percentage of threshold — comfortably under it, given the 1564 m of climbing ahead — keeps you out of trouble on the steep pitches. If you don't have a current threshold number, run the numbers through the FTP estimator before you plan the day. Then meter your effort so the steepest sections cause a brief, deliberate spike rather than a blow-up.

Gearing

Gear for the 15.2% max, not the 5.74% average. A compact 34-tooth inner chainring is the sensible front choice, and the cassette is where you buy yourself insurance. A 34×32 low gear is the minimum most riders should bring to a summit at 2286 m after 27.2 km of climbing. If you'd rather spin than grind — and on a climb with 1671 m of total ascent, most of us would — step up to a 34×34. That extra sprocket lowers your cadence floor on the double-digit ramps and protects your legs across the long middle third.

Summary

Colle della Bicocca is a patience climb: long, uneven, and unforgiving of anyone who ignores its 27.2 km length. Respect the 15.2% spikes, gear generously, and pace to the summit rather than the next bend.

Length: 27.2 km
Average gradient: 5.74%
Max gradient: 15.2%
Start: 722 m
Summit: 2286 m
Net gain: 1564 m
Total ascent: 1671 m
Category: HC