So I recently bought an old bike -- nothing new for me -- but as I was poking
around on it, I realized something was unusual: I'd bought a skiptooth bike. I had questions.
So first, what is a "skiptooth" bike? Without getting too much into bike nerdery (I do that plenty elsewhere around here) the basics are this: Modern bike chains have 1/2" between their pins, but that wasn't always the case. Up until around 1950 or thereabouts, most chains used an uneven one-inch spacing, with long links alternating with short links between rollers. This was called "skiptooth" because the sprockets were missing one tooth in between each tooth. They skipped those.
What? Yeah. Take a look at the picture above to visualize it, cause it just seems weird. Why not just make them all the same size?
Because it was mimicing an earlier 1" spacing standard from the 1890s or so called... wait for it... "blockchain."
The original blockchain literally had big 1" steel blocks, with short linking plates between them. I believe the thinking was to limit the amount of parts that bend so it would be stronger. This didn't work nearly so well for bicycles as it did heavy machinery, but it was the first viable bike chain.
An example of a blockchain as used for a bicycle. Photo from thecabe.com.
The difference, of course, between this 125-year-old tech and the modern blockchain is that a bicycle blockchain actually solved an identifiable problem.
Blockchains were inefficient and clumsy -- some things never change -- and only lasted about 20 years or so before they were replaced by the much more flexible, quieter skip tooth, which lasted about 50 years before being replaced by the standard chain spacing we've all been using for the past 75 years.
SkipToothChain: the next big thing.
I'm not proud. After all, I did make https://dadjoke.fly.dev.
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