BigWheel tm

//There were "farthingpennies", with the little wheel out front. As I have ranted elsewhere, bicycles are old technology that was and still is both expensive cutting-edge and simple garage-crazy. You are very unlikely to come up with something new in bicycles, and especially not new and useful.
— baconbrain, Jan 25 2011//

This ^ annotation posted to [VJW]'s 'Bicycle without chain' idea has been popping into my head at the oddest of times since I read it.
Waking me from a sound sleep, or while smashing my thumb with a hammer, or watching water spray from the wet-saw.
It's like this incessant niggling challenge, taunting me with its staunch irrefutability.
Affronting my senses like a fleck of tinfoil beneath a tooth filling.
A veritable plethora of unnovative cyclic angst.

<grabs rusty lance and saddles nag>
"Sancho! My helmet!"

The only new and useful thing I've been able to think of is to expand a bicycle's rear tire after top gear has been reached, letting riders gain far more speed pedaling downhill and maintain a higher overall speed on level stretches.

Interlocking semi-circular arcs comprise the outer rim of a tubeless wheel.
Tread coated on their outer surface, they are connected individually to the inner hub by a pantograph slider system. Centrifugal force causes the outer rim to expand at high revolutions allowing for a greater distance to be travelled per pedal stroke.