Lemhi Pass

Overview

Lemhi Pass is a Category 2 climb in the United States, running 10.1 km from a start elevation of 1,713 m to a summit at 2,252 m. Over that distance you gain 539 m net, at an average gradient of 5.32%. On paper that puts it in classic tempo territory: long enough to reward pacing discipline, not so steep that the average alone forces you out of the saddle.

The average, though, tells only part of the story. The climb records 695 m of total ascent against just 539 m of net gain — a 156 m gap. That means roughly 156 m of what you climb, you also give back on downhill and false-flat sections before regaining it. Every metre of that recovered elevation is a metre you have to climb twice. Budget your effort for the full 695 m of vertical work, not the 539 m the summit figure suggests.

How the Gradient Unfolds

A 5.32% average on an undulating road hides real variation. With 156 m of undulation baked in, expect the grade to swing well above and below the mean rather than holding steady. The steepest recorded ramp hits 36.62% — a wall-like pitch that will not last long but will spike your power and heart rate if you meet it in the wrong gear.

• Flatter and downhill recovery sections where the grade drops toward zero or turns negative
• Repeated short climbs stacked between those recoveries, each demanding a fresh surge
• A single steepest ramp at 36.62% that dictates your lowest gear choice for the whole ride

Pacing Notes

On an undulating climb like this, chase even effort, not even speed. Trying to hold a constant pace over the rollers forces you to hammer every rise and coast every dip — the surest way to burn matches early. Instead, anchor your effort to a sustainable power output and let your speed float: higher on the descents and false flats, lower on the pitches. Ease slightly before each ramp so you crest it under control rather than blowing past threshold. If you do not know your ceiling yet, run the numbers through the FTP estimator and set a target you can hold across all 695 m of ascent.

Gearing

The 36.62% ramp governs your setup. That gradient is far beyond what a standard road double will let you spin, so gear for the wall, not the average. Fit a compact or sub-compact chainset paired with a wide-range cassette — a 34×32 or 34×34 low gear gives you the range to keep cadence up when the road stands on end. Check your chainset and cassette before you ride; discovering you are over-geared halfway up a 36% pitch is not the time to find out.

Summary

• Length: 10.1 km
• Average gradient: 5.32%
• Maximum gradient: 36.62%
• Net elevation gain: 539 m
• Total ascent: 695 m
• Category: 2

Lemhi Pass is a straightforward Category 2 on paper that plays harder in the legs. The 156 m gap between net gain and total ascent means the rollers do real damage — pace to power, gear for the steepest ramp, and you will reach 2,252 m with something left.