by Chris Daigle, ECI #337
The bicycle is one of the most efficient vehicles ever built. It will take an individual farther for a given amount of energy than any other form of transportation. One reason for this is the simple chain drive.
Basically unchanged for one hundred years, the chain drive allows only two percent of energy to be lost between the chainrings and the cassette. By comparison, even the most fuel-efficient car loses about 80 percent of the engine’s energy before it moves the car. Complement-ing its ability to conserve power, a bicycle is one of the most frugal forms of transpor-tation, requiring less than two cents per mile to operate.
Chain Wear
The modern bicycle chain has a half-inch pitch, meaning it measures one half inch, pin to pin. One link consists of two inner plates, two outer plates, two pins and two rollers, While the pins fit tightly into the outer plates, both the inner plates and the rollers pivot freely on the pins.
As a chain wears out, so do the chainrings on your cranks and the cogs on your rear wheel. How do you prevent such damage? Well, there are a few theories about how to keep the drivetrain of your bike in good working order without spending too much money.
One theory is, “Replace Your Chain Before It Wears Out.” Keeping constant vigil over your chain by checking it monthly and replacing it as soon as it wears out will make your bike’s other parts last much longer. If you ride regularly, you may require as many as three to four chains each year, each at a cost of $30 to $150, depending on the quality of chain and labor costs.
An alternate is the “Lazy Person’s Wait Until It’s Finished” theory. This assumes that your bike will tell you when it’s ready to have its chain replaced. As chains stretch, cog sets wear out and so do small chainrings. When you pedal under load, (uphill, for example) and your chain “skips,” you are seeing the end of the road for most of your drivetrain. At this point, you need a new chain, cassette and quite possibly a new small chainring. Under normal road conditions, you might realistically expect to get two years out of these parts. Estimated cost: $70 to $200 every two to three years, again, depending on quality of parts and labor costs.
Chain Care
In order to get the maximum life from your chain, you should consider three things:
Quality of the Chain: The differences between less expensive and more expensive chains include the shape of the plates, quality of materials and the riveting of the pins. Chain side plates are designed to help the chain shift better, so better quality equals smoother shifts. Higher quality materials that are used on more expensive chains increase chain life. In addition, pins are “mushroomed” in the higher quality chains after they are pushed into the plates at the factory. This process increases the tolerances of the chain plates and makes for a stronger, longer lasting chain.
Maintaining the Chain: Regular maintenance of your chain need not be a lengthy or messy proposition. Simply put, if you see dirt on the outside of your chain, wipe it off with a rag. If your chain squeaks or is excessively noisy, it needs lubrication. Remember: if you can see the lube on the chain, it has been over-applied. Only the inside of the chain needs to be lubricated. There are many types of lubricants for bike chains-dry, wet, self-cleaning, etc. Find one that works for you and learn how to use it properly. Telling someone what type of lube to use is like telling them what kind of underwear to buy. As a general rule, if you ride where it’s wet, use a wet lube. If you ride where it’s dry, use a dry lube. To apply, pedal the cranks backwards about four times, drip the lube onto the chain, and then wipe off the excess. You may want to avoid spray applicators as they tend to be very messy to apply.
Riding on the Chain: Your riding style will affect how long your chain will last. If you ride in a high gear, the lower cadence loads the chain more than if you spin in a lower gear. The less the chain is loaded, the longer it will last. Reducing the amount of cross gearing (large chainring and large cog in the rear or small chainring and small cog in the rear) will also help improve the life of your chain. If you ride a tandem, your chain will most definitely wear faster.
Buying a Replacement Chain
It is important to ensure that your new chain is compatible with the drivetrain on your bike. There are multi-speed and single-speed chains. Check with your local bike shop about which chains they carry and which one will work with your bike. With bikes from a single gear to 30 gears, getting the right chain is very important, as one might not work with the other.
Replacing your chain need not require a trip to the local bike shop, although you will need tools. First, measure the new chain by wrapping it around your large chainring, through the front derailleur, then around the largest cog in the rear, bypassing the rear derailleur. Then, from the point where the chain comes together, add two links and cut the chain. Most new chains do not require that you use the original pin to rejoin the links. [Editor’s note: The safest way to size a chain is to count the links in the old chain and use exactly that many links in the new one.]
Understanding your drivetrain is valuable knowledge for all cyclists. Taking a little extra time to understand how it works will make you a more confident and knowledge-able cyclist and an asset to your riding partners.
Chris Daigle is an Effective Cycling TM instructor from Lafayette, La. He graduated John Barnett’s Elite Technician’s course with honors, and has six years of in–shop experience. He is now a school teacher who does independent bike work on the side. He has a grant application pending to teach cycling in the schools.
Reprinted here by permission of Bicycle USA Magazine. Bicycle USA is a member benefit of the League of American Bicyclists. For further information on the League go to www.bikeleague.org.