Colle Greguri

Overview

Colle Greguri is a hors catégorie climb, the hardest rating on the scale ahead of categories 1 through 4, and it earns that label the honest way. Over 23.2 km the road lifts you from 929 m to a summit of 2297 m, a net gain of 1368 m. The moving average sits at 5.89%, which sounds civil until you register two things: the length, and a maximum pitch of 23.79%. This is a climb you settle into for the better part of an hour, not one you attack.

How the Gradient Unfolds

Do not let the 5.89% average lull you. On a climb this long, that figure is an accountant's summary of many very different kilometres. The 1368 m of net gain is nearly matched by the 1336 m of total ascent, which tells you the road climbs almost relentlessly — there is little descending or false flat to reclaim, so the elevation you earn stays earned.

The story here is variance. A 23.79% max gradient against a 5.89% mean means the steep sections are roughly four times the average pitch. Expect long stretches near the mean punctuated by sharp ramps that spike well into the teens and beyond. Those ramps are where the climb is won or lost, and where an even-looking average hides its teeth.

Pacing Notes

The single most useful thing you can do on a 23.2 km HC climb is refuse to redline early. Set a power ceiling anchored to your FTP and treat it as a hard cap for the shallow and average sections, holding a chunk in reserve for the ramps toward 23.79%. If you have never measured your threshold, run the numbers through the FTP estimator before you go, because guessing on a climb that gains 1368 m is an expensive mistake.

A workable plan: sit slightly under threshold across the 5.89% stretches, then allow short surges above it only where the gradient forces your hand. Over 23.2 km, discipline in the first half buys you the legs to survive the summit push to 2297 m.

Gearing

Bring more range than you think you need. For most riders a compact 34-tooth inner paired with a wide-range cassette is the sensible baseline. A 34×32 will get a strong climber up the average gradients, but the 23.79% ramps are exactly where a 34×32 runs out of road and forces you into a grind you cannot sustain for 23.2 km. If your legs or your loaded weight leave any doubt, fit a 34×34 instead — that extra sprocket is cheap insurance against blowing up on the steepest pitches, and it lets you spin rather than heave your way to 2297 m.

Summary

Colle Greguri is a full-length HC test: 23.2 km of near-continuous climbing, a deceptively modest 5.89% average masking a brutal 23.79% max, and 1368 m of vertical between the 929 m base and the 2297 m summit. Pace it with your head, gear it generously, and it becomes a climb you finish rather than one that finishes you.

Length: 23.2 km
Average gradient: 5.89%
Max gradient: 23.79%
Start: 929 m
Summit: 2297 m
Net gain: 1368 m
Total ascent: 1336 m
Category: HC