Colle del Breuil cycling climb profile
Colle del Breuil is not a climb to measure by its average gradient alone. At 36km, with 2,639m of net elevation gain from 470m to 3,109m, it is an HC ascent that asks a different question than a short, steep pass. The issue is not whether you can handle a hard ramp. It is whether you can keep producing controlled power for long enough that the climb does not slowly dismantle your pacing plan.
The headline average is 7.33%, which already puts the climb in serious territory over this distance. On a shorter climb, that number would suggest sustained work. Over 36km, it becomes a durability test. You need to ride the early slopes as if the summit is much further away than it feels, because it is. The climb gains elevation relentlessly from bottom to top, and the total height difference is large enough that any early surge has a cost later.
How the gradient unfolds
The available profile data does not break Colle del Breuil into named sectors, so the cleanest way to read it is through the relationship between distance, average gradient, and maximum gradient. A 7.33% average across 36km means the base level of difficulty is already high. The listed maximum of 22.62% tells you the climb also contains much steeper moments, and those ramps are the places where pacing discipline matters most.
That combination usually changes how the climb feels. The lower part should be treated as a setup phase, not an opportunity to prove form. The middle of a climb this long is where riders often drift above sustainable effort without noticing, especially if the road feels merely hard rather than brutal. The upper part is where the accumulated elevation gain makes every over-threshold effort from earlier show up.
Pacing and gearing notes
Ride this climb from the bottom with a ceiling, not a target you chase. If you know your /glossary/ftp, keep the first sustained section under control and save the hard work for the steepest pitches. The 22.62% maximum gradient is the key gearing warning. You want a low gear that lets you stay seated and keep cadence moving when the road bites, rather than being forced into repeated low-cadence surges.
A wide-range climbing setup is the sensible choice. Even strong riders should avoid gearing that only works at threshold, because the length of Colle del Breuil makes repeated muscular efforts expensive. If you are estimating effort before riding it, use a conservative number from /tools/ftp-estimator and pace for the full 36km, not for the first hour of climbing.
The right approach is simple: protect the legs early, stay smooth through the steep ramps, and let the climb come back to you near the summit.