Colle del Preit

Overview

Colle del Preit is a hors catégorie (HC) monster, the kind of climb you plan a whole day around. Over 25.8 km it lifts you from 787 m at the base to a summit of 2454 m, a net elevation gain of 1667 m and a total ascent of 1671 m once you account for the small dips along the way. The average gradient is 6.46%, which sounds civilised until you remember it holds that figure across more than 25 kilometres. This is a climb of endurance first and steepness second — but the steepness is there when it wants to be, spiking to 14.13% at its cruellest.

How the Gradient Unfolds

The headline number, 6.46%, is an average stretched across enormous distance, so expect the road to breathe rather than sit at one pitch. The near-identical net gain (1667 m) and total ascent (1671 m) tell you almost every metre is spent going up — only about 4 m of the climb is false-flat or brief respite. That is a relentless profile with essentially no recovery downhill.

Because the maximum ramp reaches 14.13% — more than double the average — the difficulty is front-loaded into pinch points rather than spread evenly. You will roll long sections a touch under 6.46% and then pay for them on ramps well into double digits. Reading the road ahead matters more here than on shorter climbs.

Pacing Notes

On a climb this long, discipline beats bravado. Anchor your effort to your FTP and hold a sustainable percentage of it from the bottom — going into the red early on a 25.8 km HC ascent is a mistake you cannot claw back. Most riders should sit comfortably below threshold for the bulk of the climb, saving any surges for the 14.13% pinches where staying seated is impossible.

If you are not sure of your threshold, run the numbers through the FTP estimator before you go. Knowing your ceiling lets you translate the 1667 m of gain into a realistic time and stops you from cooking yourself in the first third.

Gearing

At 6.46% average with 14.13% spikes and altitude thinning the air toward 2454 m, gear low and gear generously. A compact 34-tooth chainring is the sensible front. For the cassette, a 34×32 will get most fit riders over the top, but on a climb this sustained a 34×34 gives you the extra spinning room to protect your legs across all 25.8 km. If your bike accepts it, err toward the larger cog — you will never regret an easier gear near the summit.

Summary

Colle del Preit rewards patience, low gearing, and a steady head. Respect the distance, meter your effort against threshold, and the 1667 m of climbing becomes a rhythm rather than a battle.

Length: 25.8 km
Average gradient: 6.46%
Max gradient: 14.13%
Start: 787 m
Summit: 2454 m
Net gain: 1667 m
Total ascent: 1671 m
Category: HC