Interlocking Teeth

The stepped steel sprockets of the bicycle cassette formed a precise mechanical sequence. Leaving the room behind, I navigated past the patio screen into the courtyard air, where a commuter bicycle leaned against the brick wall. Its metal frame was cool in the noon shade. Stepping from the lower chainstay toward the derailleur assembly, I examined the meshed links. With deliberate pressure, I guided a slack chain roller until it seated squarely between two tapered teeth. The symmetry engaged with a crisp, muted click. Anchoring my footing atop the cylindrical axle nut, I paused, perfectly balanced among the radial steel spokes.