Colle del Pas cycling climb profile
Colle del Pas is an HC climb built around duration first, severity second. At 32.3 km long with an average gradient of 5.06%, it is not defined by a relentless wall-like pitch from bottom to top. The real difficulty is that the climb asks you to keep producing for a long time, then still have enough control left for the steepest sections, where the gradient reaches 23.9%.
The road starts at 602 m and finishes at 2234 m, gaining 1632 m from base to summit. That tells you the tactical problem clearly: the average gradient looks manageable on paper, but the overall elevation gain and HC classification mean this is not a climb to ride on feel alone if your feel is optimistic.
How the gradient unfolds
A climb averaging 5.06% over 32.3 km usually gives riders enough terrain variation to make mistakes. The steadier sections can tempt you into pushing a little above plan because the speed still feels reasonable. The problem is that those small overreaches compound before the steep ramps arrive.
The 23.9% maximum gradient changes the character of the ascent. Even if that steepest pitch is not representative of the whole climb, it matters because it forces a different pacing model. You cannot simply ride to the average gradient. You need to preserve enough muscular strength and low-speed control to handle a section where cadence can collapse quickly if the gear is too hard.
Pacing notes
Ride the lower slopes as if the climb gets harder later, because physiologically it will. Even if the road does not steepen continuously, fatigue makes the same gradient cost more after a long ascent. Keep the effort under control early and avoid treating the gentler gradients as free speed.
If pacing by power, anchor the climb around a sustainable effort below your limit rather than chasing surges. Use /glossary/ftp as the reference point, but do not turn the opening part into an FTP test. The better approach is to cap the effort on easier sections, accept brief spikes on the steepest ramps, then settle immediately once the gradient backs off.
If riding by feel, the correct early sensation is controlled and almost restrained. Breathing should stay stable, and the legs should feel like they are working without accumulating heaviness. Once you are deep into a 32.3 km climb, any early impatience becomes expensive.
Gearing notes
Gear for the maximum gradient, not the average. A 5.06% average can make standard climbing gearing look sufficient, but a 23.9% ramp is where poor gear choice becomes a pacing failure. Choose a setup that lets you stay seated and keep the pedals turning when the road bites.
If choosing between two cassette options, take the easier one. The goal is not just to survive the steepest pitch, but to avoid burning matches so hard that the remaining climb becomes a grind. On Colle del Pas, efficient climbing means respecting the length before the steepness exposes you.