I have an older model 1400 or 2400 off-road frame. What kind of front deraileur do I need?
The 1400 and 2400 both had seat tubes that flared from and outside diameter of 28.6 about 100 mm above the bottom bracket to 30mm at the bottom bracket shell. This stiffened up the bottom bracket for increased pedaling efficiency. It made things a bit tricky for front derailleur selection. Shimano had three styles at the time:
> High mount clamp. This works fine, since the derailleur clamps above the point at which the seat tube begins to flare out.
> Low mount clamp. This won\'t work because of the flaring.
> Bottom bracket mount design. This requires a special boss on the seatmast to support the style that mounts on the bottom bracket face.
Off-road derailleurs ware almost always clamp-on. If you have a braze-on version, consider using a 31.8 clamp with reducers to 28.6mm.