mikesbytes wrote:bychosis wrote:trailgumby wrote:Eventually someone will claim that we all have to move to 13-speed cranks and single-speed hubs because, you know, unsprung mass, and then the designed obsolescence will start all over again.
Built into the frame around the bottom bracket resulting in a single cog at the crank and a single cog at the wheel
Been done already, I have a pre-WWII German Adler Dreigang lamplighter's bicycle which has a 3-speed countershaft gearbox built into a large cast triangular bottom bracket shell. The crank is only attached to the crank axle not the chainring which is driven by a tube outside the crank axle which is the final drive of the gearbox. Weighs a ton mind but it is was built not to break.
<edit> Apparently they made a 'Sports' version !
I believe there was also a two-speed bottom bracket gear in modern times used on MTB's IIRC.