Col Terray

Overview

Col Terray is a hors catégorie climb that asks for everything you have and then a little more. Over 21.5 km the road lifts you from 490 m at the base to a 2058 m summit, a net gain of 1568 m at an average gradient of 7.29%. That average alone marks it as serious, but the length is what defines the effort: at HC difficulty, this is not a climb you attack, it is a climb you survive and, if you have paced it right, finish strong.

The total ascent of 1540 m sits just below the net gain, telling you the climb is almost relentlessly upward — there are no meaningful descents to break the rhythm or let you recover. Once the gradient bites, it stays with you.

How the Gradient Unfolds

An average of 7.29% across 21.5 km is punishing precisely because it is so sustained. Spread across that distance, the climbing rarely relents, and the max gradient of 13.23% shows where the road stiffens well beyond the mean. Those steeper pitches are where riders who went out too hard start to unravel.

Because total ascent (1540 m) is so close to net gain (1568 m), you can trust that nearly every metre is spent going up. The difference — a mere 28 m — represents the only fleeting easings on the whole climb. Treat any flatter section as a gift, not an invitation to press.

Pacing Notes

On a climb this long, discipline beats bravado. Anchor your effort to a percentage of your FTP rather than to how you feel in the first few kilometres, because the first few kilometres always feel easy. If you do not know your current number, run the FTP estimator before you ride so your target is grounded in data, not optimism.

For a 7.29% average sustained across 21.5 km, most riders should settle in comfortably below threshold and hold that ceiling with religious consistency. When the road tips toward its 13.23% max, let your cadence drop and your power rise only briefly — then return to your target the moment the gradient eases. Going into the red on the steep ramps is the single fastest way to blow a climb of this length.

Gearing

Do not under-gear this climb. With 1568 m of vertical to grind out and pitches touching 13.23%, you want spinning range in reserve for the final third when fatigue compresses your usable cadence. A compact 34-tooth chainring is the sensible front choice.

At the rear, a 34×32 is the minimum most riders should consider, and many will be far happier with a 34×34. That extra sprocket keeps your cadence alive on the 13.23% ramps without forcing you to muscle the pedals — exactly what you need 15 km deep. If in doubt, take the easier ratio; you will never regret it on an HC climb.

Summary

Col Terray is a genuine hors catégorie test: long, steep, and unforgiving, rewarding riders who pace with patience and gear with humility. Respect the 21.5 km, hold your target, and the 2058 m summit is yours.

Length: 21.5 km
Average gradient: 7.29%
Max gradient: 13.23%
Start: 490 m
Summit: 2058 m
Net gain: 1568 m
Total ascent: 1540 m
Category: HC