turn of the century chainrings

Rocket Sprocket

Here is a funny little idea. Rocket Sprocket, Sprock-O-Matic, made in Miami, Florida. It would turn your bike into a 2 speed, with the chainring being elliptical. Depending upon where the ellipse was, it would make it feel like you were riding in a harder or easier gear. It was a fad, like a mechanical Shimano Bio-Pace. It works on one-piece cranks, and the "pin" on the crank would migrate from one position to the other.


I assume it didn't work well, that's why it never took off. Oval chainrings surfaces in the bike world every few decades. We collect examples, including the Thetic, Durham, and ones made by Suntour and Shimano.


The earliest oval chainring we have is on a 1893 Columbia Model 32. it is a fixed gear with elliptical chainring and it rides like a dream.

vintage packaging for various chainrings

I have always liked bicycle ephemera with an affinity toward paper-catalogs and packaging. Below are some of the envelopes that chainrings were packaged in.

I love the boastfulness of this Stronglight envelope. (what didn't they win!)

For the Stronglight Mod. 63 Super Competition chainring

TA's logo was simple and beautiful

Earlier Campagnolo envelope, for 1"pitch track chainring.

early 1980s Campagnolo track chainring envelope.

Couple of different TA chainring patterns

TA offered various chainring configurations.

TA Criterium pattern

TA 3pin Criterium triple chainring pattern

TA Randonneur pattern