Colle Bione

Overview

Colle Bione is a category 1 ascent that asks a serious question of any rider who lines up at its base. Over 16.4 km it climbs from 383 m to a summit of 1435 m, a net elevation gain of 1052 m. The average gradient of 6.41% sounds civilized on paper, but that number hides the character of the climb entirely. With a maximum pitch of 21.83%, this is not a road you can settle into and forget about. It is long enough to demand patience and steep enough in places to demand raw strength, and the two rarely arrive together.

At more than an hour of climbing for most riders, Bione sits in that awkward zone where a category 1 label undersells the effort. The total ascent of 1033 m across the profile is only slightly less than the net figure, which tells you the road climbs almost continuously rather than trading altitude on rolling terrain.

How the Gradient Unfolds

The story here is the gap between the 6.41% average and the 21.83% maximum. That is a spread of more than 15 percentage points, and it means the climb is far from uniform. Long stretches sit at or near the average, giving you a rhythm to hold, but they are punctuated by ramps that spike well into the teens and beyond. When a road averages 6.41% yet touches nearly 22%, the arithmetic guarantees there are gentler recovery sections too — you simply have to survive the steep bites to reach them.

Treat the profile in two mental layers: the sustained grind that eats the bulk of the 1052 m of gain, and the sharp punches that force you out of the saddle. Reading the steep ramps early is the difference between a controlled effort and blowing apart.

Pacing Notes

Climbs this long are won by discipline, not heroics. Anchor your effort to your FTP and hold something just below threshold for the sustained sections, keeping a reserve for the 21.83% ramps where power inevitably surges. On a 16.4 km climb, going five percent too hard in the first few kilometres compounds into a crisis long before the 1435 m summit.

If you do not know your threshold, run the numbers through the FTP estimator before you commit. Knowing your sustainable power lets you convert the 6.41% average into a target you can actually hold for the full duration, then meter the spikes without redlining.

Gearing

The 21.83% maximum is the number that should shape your setup. On a climb with a net gain of 1052 m and pitches that steep, undergear and you will be grinding a cadence that shreds your legs long before the top. A compact 34-tooth chainring paired with a wide-range cassette is the sensible baseline. A 34×32 will get most fit riders up the sustained gradients, but for the near-22% ramps at the end of a 16.4 km effort, a 34×34 buys you the extra spin that keeps your knees and your composure intact. If your bike accepts it, err toward the larger cog.

Summary

Colle Bione is a genuine test: long, steep in the wrong places, and unforgiving of a bad pacing plan. Respect the 21.83% ramps, gear low, and hold your threshold honestly, and the 1052 m of climbing rewards you with a summit worth the suffering.

Length: 16.4 km
Average gradient: 6.41%
Max gradient: 21.83%
Start: 383 m
Summit: 1435 m
Net gain: 1052 m
Total ascent: 1033 m
Category: 1