The modern bicycle chain is a marvelous piece of engineering. In the evolution of the bicycle, it is what allowed us to get away from directly driving the wheel- as in the “hi wheelers” of the nineteenth century. The chain must transfer motion from the front sprocket to the rear, shift from gear to gear, withstand tremendous pressure, and still not add significant frictional resistance to the system.
Modern chains have four different parts. Each link has inner plates, outer plates, rollers and pins. A typical bike chain has 112-120 individual links. When we replace your chain, we think of it as one part, but it’s really over four hundred fifty parts!
Bikes have many bearings, which contribute friction that we must overcome to propel the machine. Over one hundred of these bearings are in the chain, which is exposed to water, grit and dust. It’s easy to understand why chain cleaning and lubrication are so important!
Lubricating your chain is the second most frequent maintenance your bike needs after inflating your tires. I prefer drip bottles. Sprays put on too much and spray lube where you do not want it.
Your chain gets the worst effects of your ride conditions. Water tends to wash lube out. Dusts and metal particles accumulate inside your chain. Cleaning your chain extends its life, helps it shift better and be more efficient. Park Tool’s Chain Gang and the new Pedros Pig are marvelous chain cleaners. They enclose the chain while you clean. Park’s kit also includes a brush for cleaning between the cogs.
Chain wear can damage your cassette and chain rings, too. It causes the teeth on the sprockets to wear and develop a hook. If you install a new chain on a worn drive train, the chain will skip because the space between the chain rollers is shorter than the space between the worn teeth on the sprocket. Replacing the chain often preserves your sprockets. Chain wear gauges are a good tool to own. We stock three kinds; that is how important we think they are. Be sure to use a chain intended for the number of cogs you have. A new chain is a very good investment in your bike.
The finish on the chain plates and the joining of parts through the pins affect the quality and price of chains. Better chains use harder metal coatings, which increase strength and hold lubricant longer. If a chain fails or breaks it is usually caused by the pin coming loose. Better quality chains use more sophisticated methods of securing the pin.
I hope this has provided some insight into why a chain is so important and deserves proper care. Chains can also be used to lock your bike, but that is a different story and a different type of chain.