Front derailleurs, or "front mechs" as they are sometimes referred to are the mechanisms that move your chain up and down the front chainwheels and are operated via the front gear shifter. Front mechs on road and Mountain Bikes are usually attached to the frame with a simple band or clamp, but some are mounted directly to the bottom bracket. The right widths and lengths are also essential here to endure a crisp and precise gear shift every time.
