How It Works: 3 Speed Sturmey Archer AW Bicycle Gears

When I was growing up on the south shore of Long Island in the mid 60s I had the coolest bike. It was a purple Schwinn Stingray with a rear slick tire and a three speed stainless steel stick shift with a handle shaped like an eight-ball.

I was vaguely aware at the time that five and ten speed bikes had multiple sprockets on the outside of their rear axle, and that a mechanism (derailleur) moved the chain between the sprockets. But on my bike all I had was a fat shiny axle that I had to squirt a few drops of oil into once in a while. If I ever wondered what was going on inside that axle to achieve what the derailleur achieved on those other bikes, I don't recall. I was ten.
But over the years I would occasionally wonder what was going on inside that little axle, but I could never come up with even a rough guess. Recently I looked it up, and was stunned to learn how complex it is. And cool. But in all my research I never found an article that explained it quite the way I would have liked it explained to me. And so I took a shot and wrote a 'deep dive' description of how it works, loaded with diagrams and everything else I could think of.

The article has a short overview for those of you who might be a little curious but not up for the full course. But for those of you who are hungry, you won't be disappointed. The specific gearset I write about is the Sturmey Archer AW. This is the model that was on my Stingray, and it turns out this was a 'classic' for decades. And while there have been improvements over the years, the basic principles still apply to any three speed in-hub bicycle sitting in your garage today. And once you read my article you'll know what makes that slow 'tick ... tic ... tic' sound even when you're pedaling. Just in case you were wondering. The article is at my blog HERE. Thank you.