Col d'Aygues Tortes

Overview

Col d'Aygues Tortes is a climb defined by its length. At 41.4 km from base to summit, it is one of the longest sustained ascents you can ride, and it is that sheer distance — rather than any single savage ramp — that gives the col its category 1 rating. From a start elevation of 472 m it climbs to a summit of 2233 m, a net gain of 1761 m. The average gradient sits at a deceptively gentle-sounding 4.25%, but hold that figure in your mind across 41.4 km and the true scale of the effort becomes clear. This is a climb you settle into, not one you attack.

How the Gradient Unfolds

An average of 4.25% over 41.4 km means the road rarely does anything dramatic, but it almost never lets you rest either. The total ascent of 1765 m is only marginally more than the net gain of 1761 m, which tells you something important: there is virtually no descending, no false valleys, no rolling relief. The road simply climbs, and keeps climbing. Expect long, patient stretches where the gradient hovers around that 4.25% mean, broken by slightly steeper pitches balanced against slightly shallower drags. The absence of hidden descents means every metre of the 1761 m gain is earned on the way up — there is nothing to give back and reclaim.

Pacing Notes

On a climb this long, pacing is everything. The number that matters most here is your FTP — your sustainable hour power — because 41.4 km will keep you working for far longer than an hour for most riders. Ride the first third comfortably below threshold; the shallow 4.25% average tempts you to push too hard early, and the summit at 2233 m is a long way off. If you don't know your threshold, use the FTP estimator to set a realistic power target before you start, then hold discipline. The climb rewards even effort over heroics, and thin air near 2233 m will quietly sap watts in the final kilometres.

Gearing

Even a modest 4.25% average becomes punishing when it never ends, so gear for endurance rather than for the steepest pitch. A compact 34-tooth inner chainring paired with a wide-range cassette is the sensible choice. A 34×32 will suit stronger riders who want to keep a fluid cadence across the long tempo stretches, while a 34×34 gives you a genuine bail-out ratio for the higher, thinner-aired sections above where fatigue compounds. Given that you'll be turning the pedals for 41.4 km, the lower gear is rarely a mistake — protecting your legs early pays dividends near the 2233 m summit.

Summary

Col d'Aygues Tortes is a test of patience and rhythm more than raw power. Its 4.25% average hides the enormity of a 41.4 km climb gaining 1761 m with virtually no respite. Pace it smart, gear it low, and let the summit come to you.

Length: 41.4 km
Average gradient: 4.25%
Max gradient: n/a
Start: 472 m
Summit: 2233 m
Net gain: 1761 m
Total ascent: 1765 m
Category: 1