Why do we need a derailleur hanger on a bike?

Experienced cyclists pay great attention to choosing and installing derailleur hangers on their bikes. Sure enough, this spare part regularly saves owners the cost of repairing their beloved bikes.

In the essence, derailleur hanger is a compact removable plate that connects the rear derailleur to the frame. Its task is preventing damage to the frame in case of an impact or a fall.

Derailleur hangers background

In the past gear shifters were fixed directly on the frame, that’s because the frames in those days were made of steel; and although they were very heavy, it was difficult to break them. Modern frames are made of rigid but lightweight carbon fiber, or aluminum. However, the disadvantage among the indisputable advantages of these materials is their fragility: in case of a concentrated point impact, such frames are easily broken.

If the derailleur hanger is non-removable, i.e., it is a part of the frame, systematic damage to the bicycle cannot be avoided. And while a steel frame may be restored to some extent – bent back and even welded again, a frame made of aluminum or carbon fiber may actually be disposed of after deformation. These materials are not weldable, and even in case of a long restoration work, such a frame still has weak spots, not to mention the fact that such a complex repair alone may cost a new frame’s price.

This is why the invention of removable derailleur hangers turned the course of sports history in a new direction. Now only this low-cost consumable is broken in case of an impact, and can be thrown away; all other elements remain intact.

To the delight of today’s sportsmen, non-removable derailleur hangers are gradually becoming history, and are now encountered only in some bikes with titanium or steel frames. Today’s derailleur hangers have many designs; they can have different number of holes, and may be made of many materials (hardened duralumin, aluminum, carbon fiber, polymers, etc.). However, their main function remains the same – they break at the right moment, thus saving the frame.