San Boldo Pass

Overview

San Boldo Pass is a category 2 ascent that rewards patience over raw power. Over 14.8 km it lifts you from 142 m at the base to a 718 m summit, a net gain of 576 m. The average gradient of 3.9% sounds gentle, and for long stretches it genuinely is — but averages lie. Buried inside this climb is a maximum pitch of 23.84%, a wall steep enough to redraw your whole pacing plan. With a total ascent of 589 m recorded across the route, there is a little extra roll to the profile beyond the pure point-to-point gain, so you climb slightly more than the raw elevation difference suggests.

How the Gradient Unfolds

The headline number to reconcile is the gap between the 3.9% average and the 23.84% maximum. That 19.94-percentage-point spread tells you everything: this is not a climb of steady, metronomic effort. Long moderate sections in the low single digits keep the average tame, then the road ramps abruptly. To hold a 718 m summit off a 3.9% mean across 14.8 km, the easier kilometres have to be genuinely easy — which means the steep pitches are steeper than they'd feel on a more uniform climb. Expect the effort to arrive in pulses rather than a slow burn, and treat the 23.84% figure as the moment the climb decides how your day goes.

Pacing Notes

On a climb this variable, pacing by feel beats pacing by the average. Anchor your effort to your FTP and ride the flatter kilometres a touch below threshold so you have headroom for the steep ramp. When the gradient spikes toward 23.84%, your power will spike with it whether you like it or not — the trick is not to have already spent yourself on the gentle lower slopes. If you don't know your threshold number yet, run the FTP estimator before you go, then translate it into a target you can hold for the full 14.8 km. Banking a small buffer early is the single best insurance against blowing up on the wall.

Gearing

The 3.9% average does not dictate your gearing here — the 23.84% maximum does. On the moderate stretches almost any road setup spins comfortably, but the steep pitch is where compact gearing earns its keep. A 34×32 is the sensible baseline for most riders tackling San Boldo, giving you a cadence you can actually turn over when the road stands up. If you climb at lower power, prefer a slower cadence, or are carrying luggage, size up to a 34×34 for extra insurance on the wall. It is far better to have one gear in reserve than to grind to a walking pace at 23.84%.

Summary

San Boldo Pass is a deceptive category 2 climb: a friendly 3.9% average wrapped around a 23.84% sting. Pace conservatively on the easy kilometres, gear low for the ramp, and the 718 m summit is very achievable.

Length: 14.8 km
Average gradient: 3.9%
Max gradient: 23.84%
Start: 142 m
Summit: 718 m
Net gain: 576 m
Total ascent: 589 m
Category: 2