Colle di Prè

Overview

Colle di Prè is short on paper and brutal in reality. Over just 2.9 km it averages 16.58%, a number most riders associate with the steepest pitches of a normal climb rather than its overall gradient. From a start elevation of 301 m it drags you up to a 780 m summit, a net gain of 479 m packed into a distance you could ride flat in a few minutes.

Officially this is a category-1 climb, sitting one rung below hors catégorie. But the classification undersells the experience: the average gradient here is steeper than many HC monsters, and the defining challenge is not endurance over hours but survival over minutes. With a max gradient of 39.34%, Colle di Prè belongs to the rare group of climbs where traction, balance, and raw torque matter as much as fitness.

How the Gradient Unfolds

The shape tells the story. A 16.58% average across 2.9 km means there is almost no respite built into the road — the climb is relentlessly uphill from bottom to top. The gap between the 479 m net gain and the 419 m total ascent is small, which confirms there are no meaningful descents or false flats to recover on; nearly every metre you climb, you keep.

The headline figure is that 39.34% max gradient. A ramp that steep is close to the limit of what a road bike can climb seated, and it will spike your effort well beyond anything sustainable. Expect the gradient to swing hard around the average, with the steepest sections forcing you out of any rhythm you thought you had. Treat the whole climb as one continuous surge rather than a series of manageable blocks.

Pacing Notes

On a climb this steep, pacing is less about even watts and more about not blowing up on the ramps. Your FTP is a useful anchor, but be realistic: on pitches near 39.34% you will drift far above threshold whether you like it or not, so the goal is to keep the recoverable sections controlled and absorb the spikes without redlining for too long.

Before you commit, get an honest number. Use the FTP estimator to gauge your threshold, then ask whether you can hold a strong sub-threshold effort for the time it takes to cover 2.9 km at 16.58%. If the math looks marginal, start conservatively — the first ramps punish anyone who goes out hot.

Gearing

Gearing is the single biggest factor in whether Colle di Prè is rideable for you. On a 16.58% average with ramps to 39.34%, standard road gearing will leave you grinding at unsustainable cadences or walking. A compact 34-tooth chainring paired with a wide-range cassette is the minimum sensible setup.

A 34×32 is the starting point, and even strong climbers will want it. For most riders, a 34×34 is the smarter choice — that extra sprocket buys precious cadence on the steepest pitches and keeps your knees intact. If your bike accepts even lower ratios, use them; there is no shame in over-gearing for a wall like this.

Summary

Colle di Prè is a category-1 climb that punches like an HC ascent. Its 2.9 km length is almost irrelevant next to a 16.58% average and a 39.34% max — this is a test of torque, gearing, and nerve more than endurance. Bring your lowest gears and respect the ramps.

Length: 2.9 km
Average gradient: 16.58%
Max gradient: 39.34%
Start: 301 m
Summit: 780 m
Net gain: 479 m
Total ascent: 419 m
Category: 1