A ring habitat spinning at angular rate ω creates a centripetal acceleration that substitutes for gravity at the rim:
ω = RPM · 2π/60 [rad/s]
g_static = ω² R [m/s²] → divide by 9.81 for "g"
Walking along the rim changes your rotation rate relative to the inertial frame. Walking prograde (same direction as spin) adds to your effective ω; walking retrograde subtracts from it. Your apparent weight follows:
g_walk = (ωR + v)² / R (v > 0 = prograde, v < 0 = retrograde)
This is the same mechanism used to explain why astronauts jogging around a spin habitat would feel heavier moving one way and lighter the other — a real, measurable consequence of the rotating (non-inertial) reference frame, independent from adaptation or motion-sickness effects.
The Coriolis ratio 2v/(ωR) compares your own walking speed to the rim's speed; large ratios (small radius, fast spin, brisk walking) mean the Coriolis force dominates ordinary sensations and balance becomes harder. The head-to-foot gradient is the percentage difference in g between your feet (at radius R) and head (at R − 1.7 m) — a smaller radius means your feet and head experience noticeably different "gravity," which is disorienting.
The envelope chart plots your current (R, RPM) point against a commonly cited engineering rule of thumb for human comfort in rotating habitats: unadapted occupants tolerate roughly ω ≲ 14.97/√R (rpm, R in meters) before Coriolis and cross-coupled head motions start causing dizziness — larger rings can therefore spin more slowly (and more comfortably) for the same 1 g.