Road Crank Arms
Do you want to learn more about bike cranks and bottom brackets?
The cranksets and bottom brackets are responsible for transferring the cyclist's force to the chain and, in turn, to the rear wheel of the bike. They are composed of one or more chainrings attached to the cranks, at the end of which are the pedals. There is a crank for the right leg and another for the left, and they are mounted 180 degrees from each other, joined by the bottom bracket.
The chainrings are gears that move the bike's chain to transfer motion to the rear wheel through the cassette. There are different sizes of chainrings to increase transmission force and thus adjust the bike's speed to the different terrain conditions.
The bottom bracket can be considered the heart of the bike, as it is one of the most important elements of the bike, but it is not usually talked about because it is not visible. Almost all bottom brackets are sealed and come pre-assembled and cannot be disassembled, but they can be greased to improve their performance.
These bottom brackets do not offer many options for good maintenance or repair, so if they break down, it is most common to have to replace the entire bottom bracket.
Without a functioning bottom bracket, the bike's drivetrain would not work, making it impossible to ride. Bottom brackets are typically considered serviceable parts, although some modern designs are designed to be replaced rather than repaired. They use bearings to support the rotation of the crankset, which can sometimes produce creaking sounds or develop play when the bottom bracket starts to wear out.
High-quality bottom brackets are designed to be durable and low-friction, reducing power loss and increasing pedal efficiency. This is important because the drivetrain components have a significant impact on the overall performance of the bike.