Bicycle Derailleur Review

Different derailleur systems were designed and built in the late 1800s. One of the first derailleur systems was a two-speed model created by French cyclist Paul de Vivie. The first derailleur systems used rods to change gears. Over the years there were numerous innovative changes, too many to discuss here. Today, cable shifted derailleurs are used primarily on most bikes such as the Shimano Tiagra derailleur.

Derailleurs, including the popular Campagnolo derailleurs, can be purchased directly from your bike’s manufacture or you may buy aftermarket versions as well. The Ultegra derailleur is another popular derailleur made by SRAM and  to consider if you're in the market. These are pretty specific parts that usually only fit certain makes and models, so know what your bike needs before you buy anything. If you are not sure, then take your bike to a bike shop for help. Derailleurs do occasionally require some maintenance. They need to be lubed up or kept greased up. Remove any solid chunks of dirt or grime from the derailleurs using an air hose and compressor. If your derailleur gets bent at all, it has to be replaced. There are also a couple of adjustment screws that allow the derailleur to shift gears correctly. Unless you get in an accident, your derailleurs hardly ever need any attention. Just grease them up once and a while and you’re good to go.

What It’s For

There are two derailleurs on modern bikes of today. One is located at the rear of the bike and the other derailleur is located toward the middle of the bike. The rear derailleur like a, shimano rear derailleur, serves two functions. The first function is to move the chain between rear sprockets. The second function of the rear derailleur is to take up slack caused by moving to a smaller sprocket in the rear or a smaller chain ring on the front derailleur. In the relaxed position the chain is always moved to the smallest sprocket. Road racing bikes that climb hills and require rapid gear shifts to climb, use special derailleurs that allow these quick shifts to be made under the heavy load.

The front derailleur, such as a SRAM front derailleur,  has to move the chain from side to side between the chain rings as it changes sprockets. This may sound easy, but remember that the chain at this point is very tight. Also the front derailleur has to make changes in chain ring size from 53 teeth down to 20 teeth or less. It is indeed a hard working derailleur!

Major Manufacturers

Shimano derailleur, Jagwire, Campagnolo, SRAM.

Pricing

Prices on bike derailleurs can range from $40 to more than $275 for some road racing bike models.