Bocchetta Mosca

Overview

Bocchetta Mosca is an hors catégorie effort that earns its rating through sheer scale rather than a single wall of gradient. Over 42.8 km the road lifts you from a valley floor at 42 m all the way to a 2021 m summit, a net gain of 1979 m. That is a climb measured in hours, not minutes, and the length alone puts it in the deep end of the HC bracket. The average gradient of 4.63% sounds gentle on paper, but averages lie on a climb this long: the total ascent of 1966 m confirms the road pitches, dips, and recovers repeatedly on its way skyward. Come with a plan, not just fitness.

How the Gradient Unfolds

The story of Bocchetta Mosca is the gap between its 4.63% average and its 15.98% maximum. Because net gain (1979 m) and total ascent (1966 m) sit almost on top of each other, there is very little wasted descending here — nearly every metre you climb stays climbed. That means the moderate average is built from long shallow drags stitched together with sharp ramps. Expect stretches where the road barely tilts, lulling you into a rhythm, punctuated by pitches climbing toward that 15.98% figure. On a shorter climb you could muscle over those spikes; across 42.8 km, every hard ramp taxes reserves you will want at the top.

Pacing Notes

Discipline is everything on a climb of this duration. Anchor your effort to your FTP and resist the urge to chase the shallow sections at threshold — settle into a sustainable sub-threshold zone and treat the 15.98% ramps as brief, controlled surges rather than all-out digs. With 1979 m of vertical to absorb, going into the red early is a mistake you cannot claw back over 42.8 km. If you are unsure what wattage that translates to, run the numbers through the FTP estimator before you start and set a power ceiling you can honour hour after hour. Fuel and drink on the flatter drags, not the steep ones.

Gearing

Length plus a 15.98% maximum makes gearing a genuine decision, not an afterthought. A compact chainring paired with a wide cassette is the right foundation here. A 34×32 will get most fit riders over the steepest ramps while keeping cadence civil, but on a 42.8 km climb with 1966 m of accumulated ascent, tired legs late in the effort change the calculus. If you tend to grind or you are carrying luggage, step up to 34×34 for extra insurance on the pitches near 15.98%. The bailout gear you never use costs nothing; the one you wish you had costs the whole day.

Summary

Bocchetta Mosca is an endurance climb first and a gradient climb second — a 42.8 km HC ascent that rewards patience, smart fuelling, and honest gearing over raw punch. Pace it by the numbers, respect the ramps, and the 2021 m summit will come.

Length: 42.8 km
Average gradient: 4.63%
Max gradient: 15.98%
Start: 42 m
Summit: 2021 m
Net gain: 1979 m
Total ascent: 1966 m
Category: HC