Downtube shifters are a type of bicycle gear shifter that is located on the downtube of the bicycle frame, near the bottom bracket or on the head tube. They were a common feature on road bicycles in the mid-20th century and earlier and are often associated with classic or vintage road bikes. Here are some key characteristics and information about downtube shifters:
Location: Downtube shifters are positioned on the downtube, which is the diagonal tube that runs from the bottom bracket to the head tube of the bicycle frame. They are usually mounted on small bosses or braze-on fittings.
Mechanical Operation: Downtube shifters operate by using a cable to move the front or rear derailleur. When the rider moves the lever, it pulls or releases tension on the cable, causing the derailleur to shift the chain onto a different chainring (front derailleur) or sprocket (rear derailleur).
Simple and Reliable: Downtube shifters are known for their simplicity and reliability. They have fewer components than modern integrated shifters and are less prone to mechanical issues. This makes them a favorite among bicycle tourists and retro enthusiasts.
Friction vs. Indexed Shifting: Downtube shifters are available in two main types: friction and indexed shifting.
