We ride our bike every day without having to think about its design and construction. But it helps to understand more to be able to make the best use of it.
The frame of your bike is supporting all the other components and joining them together. It is also the piece that defines the type of bicycle we are riding, much more than the gears or the shape of the handlebar due to its geometry, size and stiffness.
We will take here the example of a bamboo frame. We will discuss in another post about the other available materials and their characteristics.
The different parts :
The illustration here shows us the different parts that constitute a bike frame. The general shape and elements have seen very little change over the last decades, the innovation has been focused on material technology.
Shown here is a rather traditional geometry. It is important to note how every tube has a different diameter and wall thickness according to the forces applied to each of them.
What makes a great frame?
It depends a lot on the intended use :
The innovation and marketing around cycling has been greatly derived from the "Tour de france" and other famous ultra-competitive races where the bicycles are designed only for speed. In high level racing conditions, speed equates to lightweight, high stiffness and thin aerodynamic shapes.
For bicycle touring, an additional criteria is added : durability. Lifetime is not important for high level racing as the bikes can be replaced easily, but for amateur touring it becomes important. Also the very high stiffness that is seen on racing bikes is not always desired on touring models as it generates discomfort. This means a bit of weight can be sacrificed to the benefit of durability and comfort, every person will have a different opinion on this from the very sporty ones to the more comfort-focused riders.