Why does my bike have 24 (or 21, or 27) gears? How could I possibly use them all?!! Whether you use them all or not, the gears are on your bike so you exert nearly the same amount of pedaling effort whether you are riding up a hill, down a hill, or on the flats, taking into consideration wind and road surface.

For the maximum amount of efficiency and speed on the bike and the least amount of wear and tear on your knees, you will want to maintain a pedaling cadence of 70-90 revolutions per minute (rpms). You can determine your cadence with the help of a cyclocomputer or by counting how many times one pedal goes around in a minute. When you are maintaining a steady cadence, the bike will travel different distances depending on the gear you have selected. For examples, when a bike is in 'high' gear, each revolution of the pedals propels it a long distance - perhaps 25 feet or so - but pedaling effort is very high. When the bike is in 'low' gear, each revolution propels it only a short distance, perhaps as little as five feet, but the pedals are easier to turn.

If you are riding along at 75 rpms and you approach an incline, you will need to shift to a lower gear to make pedaling easier, or you will end up standing on the pedals doing 5-15 rpms with your knees screaming. Conversely, when riding down a hill, you need a higher gear so you re not pedaling 120 rpms out of control.

If your bike has three chainrings in the front you will do much of your riding with the chain on the middle one. That means that you only have to shift the rear derailleur to find a comfortable gear. To do so, keep pedaling and use the shift lever on the right side of the handlebar or down tube to move the chain:

If the change in terrain is more pronounced, you will need to shift the front derailleur as well. The chain has the opposite effect here: Move it onto a smaller chainring (although still toward the bike) for a lower gear, and onto a larger chainring (away from the bike) for a higher gear.

Assistance for this page was provided by Richard Corbett, ECI #129. For more detailed information on gearing, including the concept of gear inches and the selection custom gearing, refer to Bicycle Gearing - A Practical Guide by Dick Marr.

Reprinted from the May/June 1995 issue of "Bicycle USA", magazine of the League of American Bicyclists.
For more information about the League of American Bicyclists, visit their web site, www.bikeleague.org, or e-mail them at bikeleague@aol.com.