Berthoud Pass

Overview

Berthoud Pass is a Category 2 climb in the United States, running 17.8 km from a start elevation of 2,667 m to a summit of 3,447 m. Over that distance it gains 780 m net, at an average gradient of 4.38%. It is a long, high-altitude effort: the entire climb sits well above 2,600 m, and thin air at the top will cost you watts even if your legs feel fresh.

The number to watch is the gap between net gain and total ascent. You climb 780 m net, but you actually accumulate 1,383 m of ascent along the way — roughly 603 m of that is bonus climbing you pay for after giving elevation back on descents and dips. That mismatch tells you Berthoud Pass is not a steady drag to the top. It undulates, and the profile hides real work that the 4.38% average never shows.

How the Gradient Unfolds

A 4.38% average on a climb that actually racks up 1,383 m of ascent means the road is far from uniform. Some sections tilt downhill or flatten to nothing, and the true climbing gets compressed into steeper pitches to compensate. Expect the grade to swing well above and below the average rather than settle.

• Flatter and recovery sections where the road eases off or drops, giving back elevation
• Repeated short climbs that re-accumulate what you lost — the source of the 603 m undulation
• A steepest ramp reaching 19.6%, a punchy wall that demands a gear in reserve

Pacing Notes

On a smooth climb you can hold even effort and let speed vary. Berthoud Pass punishes that instinct: even-speed pacing here forces you to hammer the descents and dips just to keep the number up, then you arrive at the steep ramps already deep in the red. Ride to even effort instead. Let your speed rise on the downhills, recover actively, and keep a steady output on the climbs.

Pace off your sustainable power output rather than pace or heart rate, which lags on rollers. If you do not know that figure, run the FTP estimator before you go, then hold a touch under it on the flatter stretches so you have headroom for the 19.6% pitch.

Gearing

The 19.6% maximum gradient governs your setup, not the gentle average. That is steep enough to stall a rider who came geared for a 4.38% climb. Run a compact or sub-compact chainset paired with a wide-range cassette — a 34×32 or 34×34 gives you a bailout gear for the steepest ramp without wrecking your cadence. At 3,447 m, spinning a low gear also protects you from the altitude better than grinding. Check your chainset and cassette before the ride; you cannot swap them on the mountain.

Summary

• Length: 17.8 km
• Average gradient: 4.38%
• Maximum gradient: 19.6%
• Net elevation gain: 780 m
• Total ascent: 1,383 m
• Category: 2

Berthoud Pass rewards riders who read the profile rather than the average. Pace to effort, gear for the steep ramp, respect the altitude, and the 603 m of hidden climbing becomes a managed cost rather than a nasty surprise.