"The vintage 3-speed fixed? Sure. And I've tried the modern remake, the S3X."
"Right. Well in the '30s, BSA made a 2-speed fixed hub…"
"…the Dual Purpose. And you know why it was called that?"
"Because this…" (pulls on the indicator chain on one side) "controls the speeds, and, you see this…" And as he tugs at the chain on the other side, I suddenly know, incredible as it is, the punch line that is coming... "switches from freewheel to fixed and vice versa."
Bang! There it was. Mind blown.
For several long seconds the basement is silent. And then: "These hubs are very rare. But my friend's got another one and it's built into a bike. Do you want to try it?" And soon we're en route to the BSA Gold Column.
"This hub is so good," says Nick, "someone should really do a kickstarter campaign to get them manufactured again." Nothing is impossible. But it's unlikely. The BSA DP hub is a piece of bike lore so obscure that few will ever hear of it. How improbable and delightful to have experienced one in action.