Buy front & rear derailleurs online from our Melbourne warehouse. Derailleur parts, jockey wheels, long cage derailleurs, short cage derailleurs & more.
How do I know which rear derailleur I need for my bike?
This question has a complicated answer. If you are not simply replacing your current derailleur like-for-like there are a number of things to consider.
Most importantly is the number of gears. This is the number of sprockets on your cassette, and the number of gears shown on your shifter. Commonly this will be 10-speed, 9-speed or 12-speed.
Secondly compatibility across brands is tricky. It is best practice to match your Shimano shifters with a Shimano derailleur, and a Sram shifter with a Sram derailleur. It’s even better, and preferable to match the series as well, so Shimano Deore & Sram GX series components together.
Next up is your cassette size, and the maximum cassette size. Derailleurs are designed to work with cassettes of particular ranges so that they can reach each sprocket to push the chain on to them. If you have a large cassette such as a 42T then you will need what is called a ‘long cage’ derailleur. This is just a derailleur with enough reach to get to the smallest & largest sprocket effectively.
Lastly, consider the technology you want. If you would like to upgrade your derailleur for better shifting performance, consider moving ‘series’. You can also choose electronic or mechanical!
