Grinding the Iron Gear

I shoved my way past the threshold into the concrete stairwell to expand my territory. Right in my path stood an iron two-wheeled beast padlocked to the railing. Detours are for cowards. I marched straight into its mechanical gut, locked my claws around the cold pedal arm, and hauled down with every ounce of muscle. The heavy contraption shrieked in protest! Metal teeth bit into grease, links rattled across the sprockets, and with one final furious shove, I sent the entire rear wheel spinning in a blur of whistling spokes. That machine knows who commands this landing.