Derailleurs

Off Course stocks high-quality derailleurs from Shimano, SRAM and MicroShift to keep your gear-shifts as smooth as silk.

When shopping for derailleurs, there are a couple of things that are worth bearing in mind:

How many gears:
Derailleurs are very specific when it comes to the shifts they make. Be sure to select the correct derailleur for exactly the combination of gears you have at both the (front) chainrings and (rear) cassette.

Gear Range and Derailleur Capacity:
Derailleurs will have a range of chainring or cassette “tooth count” in which they can shift gears correctly. For front derailleurs, this will be the optimum combination of chainrings the derailleur is designed for, like a 30 tooth small ring and a 48 tooth big ring.
For rear derailleurs, there will be a maximum sprocket size the derailleur can extend to. This is influenced by the length of the derailleur cage. Be sure to check that your rear derailleur will reach all the way to the biggest sprocket on your cassette.

This can also be measured in derailleur “capacity”; that is, the difference in tooth count between (big chainring + big sprocket) and (small chainring + small sprocket). Derailleurs can only accomodate so much of this difference while keeping your chain appropriately tensioned!

Pull Ratio:
Here’s where it gets a bit trickier. Derailleurs work in partnership with a gear shifter, which pulls the gear cable to perform a gear change. Different shifters, depending on brand, gear combinations and use-case, will pull a different amount of cable per shift. This is called pull-ratio. Derailleurs need to be correctly paired with a shifter that uses the same pull-ratio if they are to work well.

Finally… 1x AKA “One-by”
Drivetrains with only one chainring (known as 1x or “One-By” drivetrains) incorporate specific technologies into their derailleurs. Read more about it on this post about one-by drivetrains.

If you are in any doubt and want some advice about what derailleur is right for your bike, get in touch with us here at Off Course.