Introduction
Following the correct sequence of steps is essential if you want to set up a rear derailleur correctly. Otherwise, it can be a frustrating experience. The entire job can be time consuming, as you'll have to re-fit the gear cable and remove and replace the chain. However don't be put off, none of the steps are particularly difficult to accomplish.
This is a long guide, so you can choose to either watch the entire video above, or follow it in smaller chunks by clicking on the individual steps below.
1. Fit A Bike's Rear Derailleur
The rear derailleur is a mechanism to control the chain tension. This is necessary as a derailleur system employs different amounts of chain when running in different gears. It's other function is to push the chain left or right so that it can shift between different gears.
2. Thread A Chain On To A Bike's Rear Derailleur
If the chain looks and sounds right then it's usually following the correct path on the rear derailleur. If you're uncertain about this, look carefully at the old chain's route before you take it off, take pictures or make a sketch.
3. Diagnose Chain Length For Bike Derailleurs
On a derailleur gear system the chain shifts between cog wheels of different sizes. The system adapts to the demands for different amounts of chain with a spring-loaded arm that moves the bottom jockey wheel backwards to increase or decrease the path the chain must follow.
4. Connect A Bike's Chain With A Chain Tool
Any single-speed or standard derailer chain can be connected with chain tool. Narrow 9, 10 or '11 speed' chains have plates that are too thin to make this a reliable process and connect with special links that are supplied with them. Some chains – for example Shimano - have to be broken and reconnected with a special pin. Others with a trick link that can be dismantled by hand.
5. Set A Limit Screw On A Bike's Rear Derailleur
The rear derailleur moves the chain left and right so it engages different cogs on the back wheel. A spring pushes it in one direction - usually towards the high gears, the small cogs. A cable pulls it in the other direction.
6. Fit A Bike's Derailleur Cable
A derailleur cable doesn't need to pull as hard as a brake cable but - if the system is indexed - it needs to transmit energy precisely from the shifter to the derailleur.
7. Index A Bike's Rear Derailleur
A friction rear derailer is set-up once the limit screws are set and the cable connected. An indexed system, where the shifters click between gear positions needs to be tuned or indexed. the process of indexing is getting the hand control and the derailleur mechanism in tune with each other. Connect the cable with the derailleur in top gear, give the shifter one click. If this makes the derailleur shift one gear the cable was tight enough. If it doesn't make the derailleur shift adjust the cable until the derailleur is in a position that matches the position selected by the shifter.
8. Adjust The C-Screws On A Bike's Rear Derailleur
The last adjustment on a rear derailleur is a C-screw. This screw presses on a small tag on the the back of the gear-hanger and adjusts the position in which the derailleur rests.
Related Maintenance Tutorials
Fit A Bike's Rear Derailleur
Fit And Set Up A Bike's Front Derailleur
Set A Limit Screw On A Bike's Rear Derailleur
Index A Bike's Rear Derailleur
Fit A Bike's Front Derailleur
Fit A Bike's Derailleur Cable
Front Derailleur Adjustment & Set Up On A Bike
Adjust The C-Screws On A Bike's Rear Derailleur
Thread A Chain On To A Bike's Rear Derailleur
Fit A Bike's Saddle
Mount a Bike's Non-Derailleur Rear Wheel & Tension The Chain
Fit A Bike's Brake Cable