Colle di Sampeyre

Overview

The Colle di Sampeyre is an HC climb in Italy, running 14.3 km from a start elevation of 930 m to a summit at 2272 m. That gives a net elevation gain of 1342 m at an average gradient of 9.38%. This is a serious, sustained ascent by any measure: an average approaching double digits over more than fourteen kilometres puts it firmly in the hardest category of paved climbs.

The number that matters most here is the gap between net gain and total ascent. You gain 1342 m of altitude, but you climb 1766 m in total — a difference of 424 m. That extra distance is spent regaining ground you gave back on descending or false-flat sections. The practical consequence is that the climb is harder than a smooth 9.38% grade would suggest: every metre lost has to be re-earned, and the undulation prevents you from settling into a single rhythm.

How the Gradient Unfolds

The 9.38% average is a blend, not a constant. With 424 m of descending mixed in, there must be pitches well above the average to compensate for the flatter and downhill stretches — the maximum reaches 23.12%. Expect the effort to arrive in surges rather than a steady grind.

• Flatter or downhill recovery sections that pull the average down and account for the 424 m of extra ascent
• Repeated short climbs stacked back-to-back, each one steeper than the headline number
• A steepest ramp hitting 23.12% — a wall that demands your lowest gear and out-of-saddle force

Pacing Notes

On a climb this undulating, even-effort beats even-speed. Chasing a constant pace forces you to spike hard on every ramp and coast the descents, burning matches you cannot afford over 14.3 km. Instead, hold a steady sustainable power output through the steep pitches and let your speed fluctuate — spin faster where it eases, absorb the walls without redlining. Know your ceiling before you start: run the FTP estimator so you have a real number to pace against rather than guessing on the road.

Gearing

The 23.12% maximum gradient governs your setup. A standard compact will leave you grinding at climb-killing cadence on the steepest wall. Fit a sub-compact chainset and a wide-range cassette — 34×32 at minimum, and 34×34 is the safer choice for 14.3 km averaging 9.38% with pitches over 23%. Check your drivetrain before the ride, not at the base of the climb: confirm the cassette clears the derailleur and that you can actually reach your lowest gear under load.

Summary

• Length: 14.3 km
• Average gradient: 9.38%
• Maximum gradient: 23.12%
• Net elevation gain: 1342 m
• Total ascent: 1766 m
• Category: HC

The Colle di Sampeyre rewards riders who respect its undulation: pace by effort, gear low, and treat the 424 m of hidden re-climbing as the real difficulty rather than the average alone.