Word of the Week: Sprocket!

Bike to Work day is this Friday, so let’s celebrate with a cycling-oriented Word of the Week:

sprocket
\ˈsprä-kət\

A sprocket, as you no doubt know, is a gear with protruding teeth that can engage the links of a chain, especially a bike chain. I would argue that the sprocket is the single most essential innovation in bicycling: without the chain-and-sprocket drive train there would be no bikes as we know them, no Bike Month, no Bike to Work Day.

Time for some fun historical facts!

The very first bicycles didn’t have pedals at all: they were basically scooters that the rider would sit on and push with his or her feet. Kind of like this: 

This was thrilling enough at first, but people soon realized that scooting along in this way is pretty inefficient: with each scoot the force you exert is going down into the ground, which wastes energy and slows you down. Wouldn’t it make more sense to use those leg muscles to power the wheel directly? So some smart person attached pedals directly to the wheel and suddenly people were off in droves. 

There’s one thing about attaching your pedals to the wheel, though: if you want to go faster you have to pedal faster. And while that is pretty straightforward most people can only pedal so fast. If you want to go faster than that you have to cover more ground with each turn of the pedal—which means you have to make the wheel bigger. And since a significant subset of cyclists, then as now, are gonzo maniacs, the result was a thrill-seeker arms race as bike manufacturers tried to get more speed and more thrills out of their designs.

Which meant that pretty soon you got things that looked like this: 

People fairly regularly got tangled up in all those spokes or fell off their bikes and broke their legs or stopped short and went pitching head-first over the front wheel. Newspaper columnists tut-tutted, and mothers worried, and young people just went right on ahead riding the crazy things because that was the only way they could hook up with anyone in those benighted times and The World Must Be Peopled.

Until about 1876, when a smart fella marketed the first “safety” bicycle, which used a chain drive to transfer the power of the pedals to a nice, manageably sized rear wheel. By means of (yes!) our friend the SPROCKET.

Once there was a sprocket, people started playing around with it. It’s easier to pedal when the rear wheel sprocket is big. On the other hand, if you want to go super fast and don’t mind working harder, you’d go for a small sprocket. But how to deal with hills and headwinds and such? For a while racing bikes had a large sprocket on one side of the rear wheel and a smaller one on the other side. So to change gears, the rider had to stop, remove the wheel, turn it around so the other sprocket engaged with the chain, and then reattach the wheel. Which, in the middle of a race, tends to slow a person down.

Eventually another smart fella figured out that this was really kind of stupid: what you need is sprockets of several different sizes all mounted on the SAME side of the wheel, plus a way of moving the chain from one to another. Something that would … de-rail … the chain off one sprocket and settle it onto another. Being French, he called cette petite chose a dérailleur and then repaired to a café for some cheese and a nice glass of Armagnac.

But back to the sprocket. Which is not a French word at all. In fact it is redolent with good old Anglo-Saxon vigor.

No one seems to know its precise origin. According to the Oxford English Dictionary, the word first appeared in English in the year 1536, in the account books of St. John’s Hospital in Canterbury, viz:

To Nycoles & Horten for makyng sproketts and a grunsyll at Arnoldes ij.d

Nycoles & Horten were not building bicycles with their “sproketts”; they were providing cut timber for a building renovation. To a carpenter, sprockets are strips of wood fastened onto the end of a rafter to raise the level of the eaves and make a break in the roof line. [BTW the grunsyll (because I know that if you have made it this far you are the sort of person who WILL NOT SLEEP without knowing what a grunsyll is) is a “ground-sill”—something like a windowsill, but running along the ground at the base of the building to distribute the weight of the walls and roof. You’re welcome.] 

It turns out that St. John’s Hospital in Canterbury is still there! Check out the little dip-and-flare in the gatehouse roof—that’s the sort of thing you would do with the aid of some sprockets.   


It took another 200 years for the protrusions of the roofer’s sprocket to morph into the protrusions we see today on capstans and chainsaws and film strips—and bicycle drive trains.

But our very first recorded sprocket—our ur-sprocket as it were—was the handiwork of a couple of guys in Canterbury, who got paid two pence for their trouble. Not a bad day’s wage, actually. In 1536, half a penny would buy a quart of ale, so Nycoles and Horten presumably scored half a gallon apiece.

Thus proving that bicycles and beer have gone together since the VERY beginning.

You read it here first.

PS:  I could gild this particular lily by drawing a connection between the penny-farthing and the farthingale just coming into vogue in the mid-16th century (this was a basket-shaped cage worn under a woman’s skirts that was about as cumbersome as a penny-farthing, and a whole lot more flammable). But I believe that would be excessive.