Colle di Zambla

Overview

Colle di Zambla is a Category 1 climb in Italy, running 13.9 km from a valley start at 446 m to a summit of 1,255 m. On paper it delivers 809 m of net elevation gain at an average gradient of 5.82% — numbers that suggest a steady, mid-tier ascent. The category rating is earned through length and total workload rather than relentless steepness alone.

The headline figure to watch is not the net gain but the total ascent: 1,482 m of actual climbing over the course. That is 673 m more than the net elevation change, meaning roughly that much of your climbing is spent regaining altitude lost to descents and dips along the way. In practice, this undulation makes the climb harder than a clean 809 m profile implies. You do more work than the summit elevation credits you for, and every recovered metre costs energy you cannot bank.

How the Gradient Unfolds

The 5.82% average is a blend, not a constant. On an undulating profile like this, the average hides both the recovery stretches and the sharp pitches that spike well above it. The steepest recorded ramp hits 31.6% — a wall-like pitch you must respect and prepare gearing for, even if it is brief.

• Flatter and downhill recovery sections where you should keep pressure light and spin
• Repeated short climbs that re-earn the elevation given up on the descents
• A maximum ramp of 31.6% that will force you out of any comfortable rhythm

Pacing Notes

Because of the undulation, even-speed pacing is a trap here — holding a fixed pace over the dips means burning matches on every re-climb. Pace to effort instead. Anchor your ride to a target sustainable power output and hold it steady through the ramps, letting your speed rise on the flatter and descending sections rather than forcing pace there. If you do not know your number, run the FTP estimator before the ride and set a ceiling you can defend across all 13.9 km, including the 31.6% pitch.

Gearing

The 31.6% maximum ramp dictates your setup, not the 5.82% average. Bring a compact or sub-compact chainset paired with a wide-range cassette — a 34×32 or 34×34 gives you a bailout low enough to keep turning the pedals on the steepest wall without cross-loading your knees or stalling. Check your chainring and cassette combination before you leave; discovering you are over-geared halfway up a 31.6% pitch is not a mistake you can pedal your way out of.

Summary

• Length: 13.9 km
• Average gradient: 5.82%
• Maximum gradient: 31.6%
• Net elevation gain: 809 m
• Total ascent: 1,482 m
• Category: 1

Colle di Zambla rewards riders who read past the average. The gap between 809 m of net gain and 1,482 m of total ascent is the real story: pace to effort, gear for the 31.6% ramp, and treat every recovery section as time to save energy rather than spend it.