Cross Chaining Rubs You the Wrong Way...
Ever notice that your chain sounds and feels like it is under stress? You are probably creating this avoidable condition yourself. I have ridden by many, or more to the point, been passed by many cyclists whose bikes are emitting a terrible "metal on metal" sound. Many bike shops report that bikes coming back from a test ride and customers' bikes dropped off for repair often are cross chained. Most of these people should know better. They are performing the dreaded act of cross chaining (i.e., creating unhealthy, extreme, chain angles between the rear cogs and the front chain rings). The more the chain follows a straight line the happier it is.
Cross chaining will eventually do damage to your chain and rear derailleur. The chain is caused to bend out of its appropriate chain line putting unnecessary stress on the pivots of the chain and the rear derailleur, causing the chain to stretch unnecessarily and accelerate the wear of the teeth on the chain rings and rear cogs. This extreme angle causes the chain to ride on the edge of the gear, wearing the sides of the gear teeth and creating deformed uneven points. This wearing could eventually weaken the teeth and cause the teeth to break off, usually at the most inopportune time - like climbing, as you put immense pressure on the chain and gearing.
The damage done by consistent cross chaining becomes apparent in several ways. One problem is that extreme angles stretch the chain and the distance between the chain's links becomes greater than the distance between the gear teeth, which in turn causes the chain to skip or possibly jump off the gear altogether. The worst case scenario would be that a weakened gear tooth would break off during a climb and you could actually lose control of your bike.
Even though most fairly new tri bikes have a 9 speed or greate rear cassette (in most cases made by Shimano or Campagnolo) which would allow you 18 + different options there are several gear combinations that should never be used. These combinations consist of the chain being on the large chain ring in front (by the pedals) and the largest cog in the rear cassette (closest to the spokes) and conversely when the chain is on the small chain ring in front and the smallest cog in the rear (closest to the bike frame).
Almost all properly set up bikes will generate some rubbing of the chain/derailleur at these gearing extremes, and that is what causes the "metal on metal" sound mentioned above. You can trim (adjust) your derailleur by moving the shifting lever somewhat, but it is better to stay out of these gear selections altogether. The chain is probably rubbing on the front derailleur guide. There is nothing wrong with your bike; the problem is how you are using your bike. There are other gear combinations that will duplicate or come close to duplicating those gears that create extreme wear and tear on the system.
In reality you really only have a 16 speed bike instead of a 18 speed bike (if you have a 9 speed rear cassette). A general rule would be to stay away from the 2 rear cogs that are opposite the front chain ring. In other words, if you are using the large front ring, never use the two larger rear cogs (closest to the spokes), and if you are on the small front ring never use the two smaller cogs (near the frame). Of course there are exceptions to this rule, but in most cases the more time you spend in these gears the sooner you will be replacing gears or your chain, perhaps both. In essence your 18 speed bike could be considered a 14 speed bike.
Chain life is a very subjective thing based on many variables, such as mileage, rider's weight, weather conditions, lubrication, and the amount of time spent cross chaining. Remember that a new chain will not solve the problem of chain skipping if you have deformed gear teeth. A new chain will not mesh properly with the uneven teeth and will usually skip when pedaling hard just as your last chain did. Many pro cyclists replace chains every 1,000 miles, although a light rider who cares for the chain and pays attention to proper shifting technique may extend chain life to between 2,500 and 3,000 miles. Personally, I replace my chain every 1,500 miles usually several weeks before a big race such as an Ironman. With the price of most Ironmans exceeding $400.00, 30 bucks is money well spent. Very few things will spoil your day as much as breaking a chain during a long ride.
I use Sram chains and have had very good experiences with them. There are many other options out there such as IRD, Wippermann, and Shimano. All these chains can be found at Coloradocyclist.com as well as many other locations.
If you would like to learn more about your bike and general maintenance and repair please visit Sheldonbrown.com. The site is an excellent resource for just about any bike related topic.
Cleaning and lubrication are key to a properly functioning chain. There are many products and devices that you can use to clean your chain. Some attach to your bike, an excellent example would be a unit offered by Park Tool. This product works great and does a very thorugh job. Although chain cleaning is the best way to clean your chain short of replacement it is an inherently messy process. I prefer to use a product called White Lightning Chain Wax. Dirt seems to flake off as the wax hardens. I use a few drops before every ride.
According to White Lightning's Web site - "Original White Lightning is a totally clean, totally dry, wax lubricant. Because it contains no oil, White Lightning does not absorb dirt and grime. No oily greasy film, means no grinding paste build up on moving bike parts. As result, parts last longer, much longer! The true genius of Original White Lightning is the lubricant's "Self-Cleaning" technology, so unique it has been awarded multiple patents. When dirt makes its way to the lubricating film, release agents are activated and small particles of the wax film flake off, taking with it the contaminant, keeping parts clean and working smooth. If used regularly, you may never have to clean your chain again." I find this product to work as advertised and have been using it for the last three years with great results.
Shifting or should I say proper shifting plays big role in drive train health and saving you the waste of time and frustration of your chain jumping off the gears. When you shift you should still be pedaling, although it is best to lighten the pressure applied to the pedals and pause for an almost imperceptible split second. With practice this will become second nature. Never wait too long to shift, in other words - PLAN AHEAD! Attempting to shift to an easier gear in the middle of a hill, when you have tremendous pressure on the cranks will not do your gearing or yourself any favors and shifting may even be impossible, causing an unnecessary, and possibly embarrassing, dismount.
An easy way to understand the difference in gearing terms such as easy, hard, big and small is to remember that a big gear near the rear wheel is an "easier/lower" gear and a big gear near the pedals is a "harder/higher" gear. Continuous riding in a higher/harder gear can wreak havoc on your knees. Simply by paying attention to the upcoming terrain and shifting in proactive anticipation rather than reactively shifting as a result of difficult pedaling will make you a more efficient, fluid, cyclist which results in saving energy for more important things like GOING REALLY FAST!
©Copyright 2003 - 2015 Stephen Vincent LLC. All rights reserved®.