SPOKE

I spoke to him yesterday.

I am choosing a new spoke to repair that wheel.

What kind of spoke do you like best?

How does a spoke work?

We’ve had the wheel for a long long time.  It’s been with us so long that we have no idea who invented it.  But we do have some idea about where and when some refinements were added.

Earliest wheels were used on carts or wagons.  They were simply boards, bolted or pegged to other boards at a 90 degree angle, and then the whole works cut at the ends until it was round.  This makes something that will roll, but it can be improved upon greatly.

Some early improvements were made by the Andronovo Culture, of western Siberia.  In about 2000 BC, these folks figured out that most of that big solid wheel wasn’t needed.  They invented the Spoke.  Turns out that a spoked wheel is lighter and stronger.  We are here talking about a wooden spoke.

In the case of wood spokes, the spokes are loaded in compression.  That is, the weight presses down on each spoke, in turn, at the bottom of the wheel.

Incidentally, the word “spoke” comes from the method of manufacturing the product.  A tree, after cutting was split lengthwise into four to eight sections.  These sections were called spokes.  Because they ran lengthwise, in the same direction that the wood of the tree supported the weight of the tree, they were ideal to be formed into things that supported weight…  Like the spokes of a wheel.  The tool that was used to form the tree-spokes was called a “spokeshaver.”  Eventually, the product came to be named for the material it was made from.

The wood spoke lasted a long time.  The “wire spoke” It wasn’t until the middle of the 19^th century.  It is significant in that it is no longer compression loaded.  “Wires” or “spokes” of drawn steel were attached to the hub and the rim and tightened.  This formed a “wire wheel.”  In the wire wheel, the spokes are loaded in tension.  The load literally hangs from each spoke in turn, with the load distributed around the tensioned rim.  It is this technique that makes the modern bicycle wheel.

Since steel has a terrific tensile strength (you can pull on it real hard before it breaks) it is possible to make a wheel of this type that is both enormously stronger and many factors lighter than one that has to rely on compression of a wooden spoke.  If we had to rely on wooden compression loaded spokes, each of our bicycle wheels would weigh in at about 25 pounds.  (I can’t imagine that riding such a beast would be a lot of fun.)

Our spokes support us.  They carry our weight by hanging it from the rims of our wheels.  They hold the wheel in shape, and they take the loads from our cornering, accelerating, and braking.  Each one of these marvels weighs only a few grams.

When was the last time you thought of your spokes, or gave them a “thank you”?