Castagnola Pass

Overview

Castagnola Pass is a 10.4 km category-3 climb that begins at 67 m and tops out at 476 m, a net elevation gain of 409 m. The average gradient reads a modest 3.94%, which on paper suggests an easy tempo effort. That number, though, hides the real character of the ascent: with a maximum pitch of 13.33%, the climb is far from uniform. The recorded total ascent of 392 m is slightly less than the net gain, a sign that the road climbs almost continuously rather than trading punchy rises for descents.

How the Gradient Unfolds

A 3.94% average across 10.4 km would be gentle if the road held that slope the whole way. It does not. The gap between the 3.94% average and the 13.33% maximum tells you the effort is lumpy — long stretches sit below the average, banking easy metres, while short ramps rear up to more than three times that pitch. Expect to settle into a rhythm on the shallower sections, then have that rhythm broken by steeper kicks that demand a hard surge or a quick shift down the block. Because the total ascent (392 m) tracks so closely to the net gain (409 m), there is little respite in the form of false flats or downhill recovery; the metres accumulate steadily from 67 m all the way to the 476 m summit.

Pacing Notes

On a climb like this, the smart approach is to ride the average, not the maximum. Aim to hold a steady power near your threshold on the shallow sections and let your effort — not your speed — climb on the 13.33% ramps. If you have a power meter, anchor your pacing to a percentage of your FTP rather than chasing a target speed, since speed will swing wildly between the flatter run-ins and the steep pitches. Riders who go deep into the red on the first ramp usually pay for it before the 476 m summit. Not sure of your threshold number? Use the FTP estimator to set a realistic ceiling before you start, then leave a little in reserve for the steepest kicks near the top.

Gearing

The 3.94% average does not require exotic gearing, but the 13.33% maximum does. A compact 34-tooth inner chainring is the sensible starting point. Pair it with a 34×32 for most riders — that gives you a spinnable gear on the steep ramps without over-gearing the long shallow stretches. If you carry any extra weight, ride tired, or simply prefer a higher cadence when the road tilts to 13.33%, step up to a 34×34. That extra sprocket buys you the low-end range to keep the pedals turning smoothly over the summit instead of grinding to a near-standstill on the worst pitch.

Summary

Castagnola Pass rewards patience: a category-3 effort whose 3.94% average masks a 13.33% sting. Ride the shallow sections economically, respect the ramps, and you will reach the 476 m top having gained 409 m from the 67 m start with plenty in the tank.

Length: 10.4 km
Average gradient: 3.94%
Max gradient: 13.33%
Start: 67 m
Summit: 476 m
Net gain: 409 m
Total ascent: 392 m
Category: 3