A bicycle derailleur is a mechanism that changes gears by moving the chain from one cog to another. Here is an overview of how it works and a list of the major brands, standards and specificities by practice:
How a bicycle derailleur works:
1. Gear levers:
The derailleurs are controlled by gear levers located on the bike's handlebars. By operating these levers, the derailleur cable is pulled or released, causing the derailleur to move.
2. Front and rear derailleurs:
Modern bicycles generally have two derailleurs: one in the front and one in the rear. The front derailleur moves the chain between the chainrings (the cogs at the front), while the rear derailleur moves the chain between the cogs (the cogs at the rear).
3. Derailleur hangers:
Derailleurs are mounted on derailleur hangers attached to the bicycle frame. These dropouts allow you to adjust the position and alignment of the derailleur in relation to the sprockets.
4. Cable tensioner:
The cable tensioner is a device that adjusts the tension of the derailleur cable. It is usually located near the gear levers on the handlebars.
5. Adjustment screw:
The derailleurs are equipped with adjustment screws that allow you to adjust the cable tension and the alignment of the derailleur in relation to the sprockets.
Major brands of bicycle derailleurs:
-Shimano
-SRAM
-Campagnolo
Standards and specificities by practice:
1. Road:
- Road derailleurs are designed to be lightweight and provide fast, precise gear changes.
- Compact and dual gear groups are common for road bikes.
- Major brands like Shimano and SRAM offer specific ranges for the road, with series like Shimano Dura-Ace, Ultegra, 105 and SRAM Red, Force, and Rival.
2. MTB (All-Terrain Bike):
- MTB derailleurs are designed to be robust and shock resistant.
- Gear groups are often larger to cope with a variety of terrain.
- Major brands like Shimano and SRAM offer specific ranges for mountain biking, with series like Shimano XT, SLX, Deore and SRAM XX1, X01, GX.
3. City bike and electric bike:
- Derailleurs for city bikes and e-bikes may vary depending on manufacturer preferences and specific bike needs.
- Some brands offer derailleurs specially designed for electric transmission systems.
Each brand and model of derailleur may have its own specifics in terms of design, technology and functionality, but all follow the same basic principle of moving the chain between cogs to change gears.