Shimano's CX70 Front Derailleur was designed from the ground up for the uiquely punishing world of cyclocross. Mud-shedding plates fight back against ice and debris build up. Reinforced pins stiffen the plates for fast shifts under the worst conditions, while special attention has been paid to the derailleur pivots and arms so they shed mud and ice. The cage size is optimized for the close-ratio chainrings common on cyclocross bikes. The CX70 Front Derailleur is available as either a top or bottom pull model to suit your bike.
Capacity is calculated by subtracting your smallest chainring's tooth count from the largest chainring's tooth count. Example: 46/34/24 chainrings: 46 - 24 = 22-tooth capacity.
Bottom-pull derailleurs are used when the cable is routed underneath the bottom bracket and up through the cable clamp. Top-pull derailleurs work with frames where the cables are routed down from the top tube.
Your seat-tube diameter determines the needed derailleur clamp size.
