The gearing system on your bike is, next to your brakes probably the next most important part of the bike (assuming you also include the chain). In this section we provide a quick summary of the different components within the gearing system and the different types of them.
Mountain Bike Rear Derailleur
This has a long chain cage and is usually controlled by a handlebar gear shifter.
Road Racing Rear Derailleur
This has a short chain cage. This keeps the weight of the bike down and makes gear changing easier. The shifter on the down tube of the frame or STI/Ergo power levers, on the handlebars controls it.
Economy Rear Derailleur
This one is made of steel. It bolts straight into the frame rather than onto a gear change hanger.
Mountain bike front derailleur
This has a wide chain cage to accommodate triple chain rings that have big jumps in size between them. An indexed shifter on the handlebars controls them.
Road racing front derailleur
This is a light chain cage is less wide to accommodate the 2 chain rings normally present on this type of bike.
Five or Seven-Speed Hub Gears
They are designed as low-maintenance gears for city bikes. Again a click shifter of some description fitted on the handlebars controls these.
Three-speed hub gears
These are for utility bikes and have a click shifter on the handlebars.