Colla dei Termini

Overview

The Colla dei Termini is one of those climbs that leaves no room for negotiation. Over 12.1 km it averages 10.79%, a figure so high that it comfortably earns an HC (hors catégorie) rating — the hardest classification there is, sitting above categories 1, 2, 3 and 4. You start at 699 m and finish at 2006 m, a net gain of 1307 m packed into a road that barely relents. With a total ascent of 1287 m recorded across its length, almost every metre of forward progress is also a metre of vertical work.

An average gradient near 11% is not a number you outlast with fitness alone; it demands respect from the first pedal stroke.

How the Gradient Unfolds

Think of this climb less as a series of switchbacks to be ticked off and more as a sustained, relentless wall. The 10.79% average tells you the road rarely eases, and the 22.26% maximum gradient tells you that when it does change, it changes for the worse. That peak pitch is more than double the average — a spike steep enough to force you out of the saddle or slow you to a crawl.

Because the net gain (1307 m) sits slightly above the total ascent (1287 m), there is effectively no meaningful respite: no descents to recover, no flat kilometres to reset your legs. Every section of the 12.1 km contributes to the climb. The difference between those two figures — just 20 m — confirms this is a road that climbs, and keeps climbing.

Pacing Notes

On a climb this steep, pacing is survival. The temptation is to attack the early ramps while your legs feel fresh, but with 1307 m of gain ahead, an over-cooked start on a 10.79% average will cost you dearly before the summit at 2006 m. Anchor your effort to your FTP and hold something in reserve for the 22.26% pitches, which will spike your power and heart rate whether you like it or not.

If you don't know your threshold, run the numbers through the FTP estimator before you go. Riding a sustained 12.1 km at this gradient near or above threshold is a fast route to blowing up — aim to sit just below it and let the steepest ramps be the only moments you dip into the red.

Gearing

Do not under-gear this one. On a 10.79% average stretching across 12.1 km, and with ramps hitting 22.26%, your cassette is your best friend. A compact 34-tooth front paired with a 34×32 setup is the sensible minimum for most riders, and many will be far happier with 34×34, which gives you a genuinely rescue-low ratio for the worst pitches.

The extra range of 34×34 keeps your cadence alive when the road bites hardest, sparing your knees and letting you spin rather than grind toward the 2006 m summit. If your bike can take it, fit the bigger cog.

Summary

The Colla dei Termini is a pure test of steep-climbing resolve: 12.1 km, an HC rating, and an average that punishes any rider who starts too hard. Gear low, pace to your threshold, and treat the 1307 m of gain with the seriousness it deserves.

Length: 12.1 km
Average gradient: 10.79%
Max gradient: 22.26%
Start: 699 m
Summit: 2006 m
Net gain: 1307 m
Total ascent: 1287 m
Category: HC