Unbound 100 is 103 miles on the flint gravel of the Kansas Flint Hills in late May or early June — chunky, sharp rock that slices sidewalls, and clay that turns to tire-clogging mud when it rains. The climbing is modest, but the heat is real and the surface is relentless: it’s a day decided by durability, tire choices, and staying fueled in the sun far more than by raw fitness.

This is a twelve-week plan for Unbound’s distance and heat, built around four to six hours a week. Most rides build endurance or get you used to riding steady in heat — the two things the day asks for on limited hours.

WHAT'S INSIDE

• Structured workouts on your calendar, with real power and heart-rate graphs


• Strength work built in, with video walkthroughs


• Weekly notes from me, plus the Gravel Grit mental program


• A testing week and a mid-plan retest, so the plan runs on your real numbers


• The full Unbound Gravel 100 guide — terrain, gearing, fueling