How derailleurs shift while pedaling

Transcripció

The rear derailleur is the mechanism that shifts the chain at the rear sprockets, and it uses a cage with two pulleys: the lower tension pulley and the upper guide pulley.<sup class="text_citation" source_id="1"></sup>

As the rider turns the shifter, cable tension moves the derailleur linkage sideways, and the chain is guided onto a new sprocket while the return spring moves it back when the cable is released.<sup class="text_citation" source_id="1"></sup>

Smooth shifting comes from timing and light load: shift while pedaling, do it early before a hill, and ease the pressure if you must change under strain.<sup class="text_citation" source_id="3"></sup>