7-8-9-speed rear derailleurs

A derailleur is a component of a bicycle's drivetrain that is responsible for moving the chain between the various cogs on the rear cassette.
The number of derailleur speeds is determined by the number of sprockets on the cassette. Depending on this, it is necessary to select a compatible derailleur.
There are several factors to consider when choosing the right 7-, 8- or 9-speed derailleur to ensure compatibility and optimal performance.

Cage length: Shifters are produced with short, medium and long cages. The length of the cage is mainly determined by the transmission range of the cassette.
Make and model: When choosing, stick to reputable brands that are known for producing reliable components. See reviews and recommendations for specific models. Popular brands include Shimano, SRAM, microSHIFT and Campagnolo.
Mounting type: There are various mounting options, including direct mounting and frame end mounting. Make sure it fits your bike frame.
Weight: Consider the weight of the derailleur, especially if you're shedding grams from the weight of the bike. However, keep in mind that other factors are also decisive, such as durability and functionality.

By considering these factors, you'll be better prepared to choose a rear derailleur that fits your bike, riding style and preferences.

Is it possible to use 7-, 8- or 9-speed derailleurs with a cassette with a different number of speeds?

No, it is generally recommended to use a derailleur that matches the number of gears on your cassette. Cassettes with different speeds have specific spacing between the sprockets to accommodate the width of the chain. Using a derailleur designed for a different number of gears may result in poor shifting performance.

Can I convert my 7- or 8-speed to a 9-speed?

Upgrading a 7- or 8-speed to a 9-speed system may require more than just changing the derailleur. This will require replacing the shifter, derailleur, cassette, chain and possibly the cassette nut to accommodate the width of the 9-speed cassette.

Is it possible to use 7-, 8- or 9-speed derailleurs with derailleurs from another brand?

In most cases, derailleurs and gear levers from different brands are compatible as long as they have the same number of gears. However, there may be some differences in cable tension ratios between different brands.

What is the difference between 7-, 8- and 9-speed derailleurs?

The main difference lies in the distance between the pulleys. In addition, derailleurs with a higher number of gears may have a different length and construction of the arm to suit the specific range of gears.

What are the common problems with 7/8/9 speed derailleurs?

Common issues include poor shifting performance, gear skipping, excessive chain noise, or difficulty shifting certain gears. These issues can be caused by incorrect settings, cable tension issues, worn components or damage to the derailleur itself.

By considering these factors, you'll be better prepared to choose a rear derailleur that fits your bike, riding style and preferences.

Check out our video How to replace the rear derailleur?