Somewhere To Sit: The Frame
The frame is the most significant part of almost any pedal cycle. It defines what the machine can be used for, not only from its own character but also by dictating what other bits can be fitted. A traditional bike frame is made from tubular metal. Tubes have a much better strength-to-weight ratio than solid rods. It can take many forms, and be made from a range of materials but the classic shape is two triangles. This pattern is sometimes referred to as a diamond-frame. If the frame has no top-tube it's an 'open' or 'step-through' frame. The difference between a diamond and step-through frame is sometimes gendered. A machine without a top-tube may be called a 'ladies-bike', but anyone who rides in long flowing clothes – a catholic priest for example – may benefit from an open frame. Bikes with a low step-over are useful for riders with mobility problems and also make it easier to manage heavily laden bikes. A fully triangulated diamond frame is intrinsically stronger than a step-through.