Union Pass

Union Pass cycling climb profile

Union Pass is a Category 1 climb in the US that asks for sustained climbing discipline rather than one explosive effort. The headline numbers are clear: 15.8 km at an average gradient of 6.2%, starting at 2114 m and topping out at 3092 m. That gives the climb its defining character. It is long enough that pacing errors compound, high enough that effort control matters, and steep enough that you cannot simply carry speed through the hard moments.

The summit sits 978 m above the start, so the ride is fundamentally about managing a long vertical gain. A 6.2% average over this distance is not brutal in isolation, but the cost comes from duration. If you ride the first part like a short hill, the upper section becomes less about fitness and more about damage control.

How the gradient unfolds

With only the full-climb statistics available, the safest way to read Union Pass is as a sustained ascent with sharper interruptions. The average gradient of 6.2% tells you the climb keeps applying pressure for nearly the entire 15.8 km, while the maximum gradient of 11.5% shows there are sections steep enough to break rhythm and force a gear change.

That gap between the average and maximum is important. Union Pass is not defined by a single savage wall, but the steepest ramps are hard enough that riding at threshold too early is a poor trade. The correct approach is to assume that the 11.5% sections can arrive when you are already carrying fatigue. That changes the pacing logic: preserve torque, keep cadence available, and avoid burning matches just to hold speed on the early gradients.

Pacing and gearing notes

Treat the lower slopes as the control phase. The climb starts at 2114 m, so even before the road rises toward 3092 m, this is not a low-elevation effort. If you pace by power, keep the opening effort below your ceiling rather than chasing a target speed. If you pace by feel, the right sensation early is restrained and repeatable, not urgent.

A compact or climbing-friendly setup makes sense here because the steepest gradient reaches 11.5%. The goal is not only to survive that pitch, but to keep pedalling smoothly without being forced into low-cadence grinding. Once cadence drops too far on a long climb, muscular fatigue can become the limiter before aerobic fitness does.

Practical approach:

• Ride the first half conservatively, especially if using /glossary/ftp as your pacing anchor.
• Save one easier gear for the steepest ramps rather than shifting only when cadence has already collapsed.
• Let speed fall on the 11.5% sections instead of pushing above sustainable effort.
• Build the effort only after the climb has clearly settled and the summit is within reach.

Union Pass rewards patience. The numbers point to a climb where the decisive factor is not a single attack, but whether you can keep producing controlled power across 15.8 km while the elevation gain and intermittent steeper grades slowly narrow your margin for error.