The Skilful Rear Derailleur is perfect for getting that 7 speed drivetrain running smoothly. Featuring a lightweight nylon body, with sturdy aluminum framing and pulley arm, the Skilful Derailleur can take a hit, while still bringing reliable shifting. With an upper range limit of 36 teeth and a lower range limit of 11 teeth, this bike derailleur is perfect for a wide range of bike cassettes. This rear derailleur also features 12 tooth jockey wheels and a 6 inch long pulley arm to help make sure your chain glides smoothly through the derailleur.

On a bicycle with multiple speeds, the rear derailleur is one of the most important parts of the bike’s drivetrain. The derailleurs are what allow the rider to move the chain to different sized gear rings to make it either easier or harder to pedal. This is especially important for changes in elevation while riding. If you are climbing up a hill, the last thing you want to do is make the bike more difficult to operate, so you shift into a gear that makes it easier to pedal. On the flip side of this, if you are going really fast, you want to keep delivering power to your bike and keep that speed going. The rider can shift into a “higher gear” to get more resistance while pedaling, helping keep that speed. Being able to modulate the resistance of your bicycle like this is crucial to having an enjoyable ride, especially if you ride where it is hilly. But how do rear derailleurs work?

Rear derailleurs use cable tension to work in conjunction with the bike gear shifters to move the chain around on the drivetrain. The chain gets moved around on the front chainrings and the rear cassette rings. Different sized rings will give different riding resistances depending on whether it is in the front or the back of the bicycle. For the chain to move, first the shifter has to click to initiate everything. In the bike shifter, The shift cable end it slotted into a holding spot, which then will rotate around as it is pulled. When you click the gear shifter, it pulls the cable by a set amount of length. This set amount of length pulled to the amount of distance a derailleur will travel is called the pull ratio. Different brands have slightly different pull ratios, so you should always be aware of what brands you are interfacing with. It is generally best to not mix and match different bike derailleurs and shifters. This pull ratio is set so that when you click the shifter, the derailleur gets moved into a set position to move the chain onto another chainring. In addition to the cable tension adjustments needed to make sure the bike derailleur is running perfectly, there are upper and lower limits that must need to be set on the rear derailleur. These upper and lower limits are set by 2 different limit screws in the bike derailleur, often denoted by an "H" and an "L" (for high and low).

Dialing these screws in decreases the max amount they can go in one direction, while unscrewing them increases the distance they can go. But what does this mean? If your upper limit screw is not set properly, when you shift into your largest cassette ring, the rear derailleur may move the chain too far and make it go past the last chainring, making the chain go into the spokes of the wheel. So the limit screws on the rear derailleur make sure that the chain does not get moved where it shouldn’t!