A Chain and Sprocket Test

I climbed down from the handlebar to inspect the lower drive assembly of the bicycle. The rear derailleur hung low above the asphalt. I crouched near the small jockey wheel, reaching out to test the link tension of the greasy steel chain. With steady pressure, I nudged the lower pulley backward against its return spring. It pivoted cleanly, allowing a slight slack before snapping taut again against the teeth. The grease held a few grains of street dust, but the mechanical alignment remained true.