Taboose Pass

Overview

Taboose Pass is a hors-catégorie (HC) climb in the United States, running 11.9 km from a valley floor at 1,449 m to a summit of 3,474 m. Across that distance it delivers 2,025 m of net elevation gain at an average gradient of 17.08% — figures that place it firmly among the hardest sustained ascents you can attempt. There is no easing into a climb like this; the elevation profile goes up and stays up.

The total ascent is 2,087 m, 62 m more than the net gain of 2,025 m. That gap is small relative to the total, but it tells you the road undulates rather than climbing in one clean line — there are brief downhill or false-flat stretches you must re-climb. On a wall this steep, every re-climb costs more than the numbers suggest, because you carry no momentum into the next ramp. Budget for it.

How the Gradient Unfolds

A 17.08% average is not a number you hold evenly. It hides both the recovery breaks that let your legs reset and the ramps that spike well beyond it. The mean is a blend, not a description of any single moment on the road.

• Short flatter or recovery sections where the grade briefly relaxes — use them, do not attack them.
• Repeated short climbs stacked back to back, each one demanding a fresh surge.
• A steepest ramp that sits far above the 17.08% average, where cadence collapses and it becomes a grind.

Pacing Notes

The undulation here rewards even effort, not even speed. Chasing a constant km-per-hour figure will blow you up on the ramps and leave you coasting the brief flats. Instead, hold a steady power target and let your speed swing with the gradient — slow on the steep pitches, faster where it relaxes.

Anchor that target to your sustainable power output and ride the steepest sections just under it, so you have something left when the road re-climbs after each dip. If you do not know your number, run the FTP estimator before you commit to a plan. On a climb of this length and grade, starting 5% too hard is the difference between finishing and walking.

Gearing

The steep pitches govern your gearing, not the average. Come with a compact or sub-compact chainset and a wide-range cassette — think 34×32 or 34×34 at minimum. On the steepest ramps you will want every tooth you have to keep the cranks turning above a survivable cadence.

Check your setup before the ride, not at the trailhead. Confirm the cassette, chainring, and rear derailleur capacity actually match, and test the low gear on a hill at home. There is no bailout gear on Taboose Pass once you are committed.

Summary

• Length: 11.9 km
• Average gradient: 17.08%
• Net elevation gain: 2,025 m
• Total ascent: 2,087 m
• Category: HC

Taboose Pass is a genuine HC test: 11.9 km, 17.08% average, and 2,025 m gained to a 3,474 m summit. Respect the gearing, pace by power, and treat the undulation as the trap it is — this is a climb you finish by starting conservatively.