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Bike Chain

   I was at work trying to think of bike related topics to discuss, when I realized the answer was right in front of me. I was disassembling a large chain drive system in a piece of construction equipment. The machine was one of those skid steer loaders, the kind you see at every construction site. A machine like this was probably employed at some point in the construction your home.

 Chain drive is an amazingly efficient mode of power transfer. You've seen it lift your garage door, and it's used to spin camshafts on most car engines. Through the 1920's and into the 1940's chain drive was used commonly on heavy trucks before driveshafts came into fashion. Imagine someone's great grandfather hauling a load of logs up a steep hill in a 1927 chain drive Mack, then think about how much it sucks when your chain drops off.

 That reminds me, have you ever seen a shaft-driven bike? It's a thing that is real.
 Image result for shaft drive bicycle

  I saw a little kid's bike that was shaft-drive. It was kind of cool that the rider would never have grease on their pant leg, but the down side was that it was a direct drive system. The bike couldn't freewheel, like a fixie. I can't imagine the affect that would have on a kid if the first bike they learn to ride is a fixie.
Image result for hipster kid
  A quick search just taught me that shaft bikes are actually available with freewheels and  gears, so that's kind of neat. If you really despise grease on your pant leg, you can buy a super obscure  shaft-drive bike...or you could just get a chain guard.
The CeramicSpeed DrivEn system would have to be built into new bikes – it couldn't be retrofitted to existing models
  Or try this new lever drive bike, it's like the Shake Weight© of bike technology. 
          The NuBike road bike prototype – other models are in the works
  The bike chain we know and love hasn't always been the only choice. Current chain is actually known as 'roller chain' since it's comprised of plates that hold individual  rollers. Early bikes used a system called 'block chain.' This chain had solid blocks as inner links, instead of rollers.
Image result for vintage bicycle blockchain
  Eventually this was replaced by 'skip link' chain. This type of chain has the same number of rollers as a similar length of normal chain, but they are spaced alternately close together and far apart. Every other roller engages a sprocket tooth. I have this set up on my pre-war Firestone ladies bike, it's very cool.

  I can say it's pre-war, because WWII brought the end of chain variations. Once we started making bikes again they all ran on standard 1/2" pitch roller chain.  Now chains just keep getting narrower and narrower as we are able to stack more cogs on the hub. But the principle is the same for every application of chain drive. It is strong and dependable. The downsides of chains is their tendency to stretch and wear into the drive cogs. Also they are susceptible to dirt and grime build-up which can lead to poor shifting and even dropping off the cogs completely.
  We can't say how long the chain will continue its dominance. One new contender is the Gates Belt Drive. This system uses a belt to replace the chain on single speed bikes. It can't be used with external gears, but it seems to provide excellent power transfer with less friction and noise than a chain.
Image result for gates belt drive
Like pneumatic tires and disc brakes, some new technology will eventually prove to be better than what we have now. But until then, go wipe down your chain and drop some lube on that puppy.
   I looked up some terminology and definitions at the best website for old bike stuff,  Sheldonbrown.com . Sheldon was an old bike guru and a human encyclopedia of bicycle knowledge. His website was one of the first things I discovered on the internet, and I immediately fell into the deep rabbit hole of cool old bike info. He has written  repair procedures for three-speed hubs as well  as charts you can use to find the build date for Huffy's, Schwinn's and a few other brands. If you ever end up with some obscure brand of vintage bike that you don't know anything about, visit his site and you are bound to learn something new.

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