Coll de les Tres Creus

Overview

Coll de les Tres Creus is an hors catégorie monster that stretches for 24.9 km at an average gradient of 6.21%. It lifts you from a valley floor at 132 m all the way to a summit of 1677 m — a net elevation gain of 1545 m, with 1550 m of total ascent once the small dips and recoveries are counted back in. That extra 5 m of climbing beyond the net figure tells you this is an almost uninterrupted upward drag rather than a rollercoaster: there is very little downhill to give back.

At nearly 25 km in length, this is an endurance climb first and a gradient challenge second. The HC classification is earned not by a single savage wall but by sheer accumulated work: sustained effort for the better part of an hour or more, with the altitude gain doing the damage.

How the Gradient Unfolds

A 6.21% average across 24.9 km is deceptively hard. Because the climb barely relents — total ascent of 1550 m sits just 5 m above the net gain of 1545 m — the road keeps pointing up almost the entire way. There are no long flat plateaus to soft-pedal and recover.

Expect the gradient to hover around that 6% mark for long, grinding stretches, with steeper ramps offset by shallower sections that never quite become rest. Because the summit sits at 1677 m, thinning air late in the effort adds a subtle tax to the final kilometres that the raw percentage doesn't capture.

Pacing Notes

On a climb this long, discipline beats ambition. Anchor your effort to your FTP and aim to hold a steady percentage of it rather than chasing the front of the group early. A sustainable target for a climb approaching an hour is typically just below threshold — start conservatively over the first few kilometres, then settle in.

If you don't know your current threshold, run the numbers through the FTP estimator before you ride so your power targets are grounded in reality. Over 1545 m of gain, going 20 watts too hard in the opening kilometres will cost you far more than that near the top.

Fuel and drink on a schedule, not on feel — at 24.9 km the effort outlasts your body's early reserves.

Gearing

For an HC climb of 24.9 km at 6.21%, gear low and protect your legs. A compact 34-tooth inner chainring paired with a wide-range cassette is the sensible baseline. A 34×32 will get most fit riders up the steady sections at a workable cadence, but on a climb with 1545 m of relentless gain, a 34×34 buys you crucial extra spin when fatigue bites in the final third.

If your bike accepts it, the slightly easier 34×34 is the safer choice here — spinning a lighter gear at higher cadence spares your muscles over a climb this long. There is no reward for grinding a gear that's too big when the summit is still kilometres away at 1677 m.

Summary

Coll de les Tres Creus is a true HC test of patience and pacing: 24.9 km, 6.21% on average, and 1545 m of climbing from base to summit. Ride it steady, gear it low, and let the numbers — not your ego — set the tempo.

Length: 24.9 km
Average gradient: 6.21%
Max gradient: n/a
Start: 132 m
Summit: 1677 m
Net gain: 1545 m
Total ascent: 1550 m
Category: HC