28.6 mm front-derailleur clamp (28.6 mm band)
Which frames use a 28.6 mm band front-derailleur mount, and how to tell band from braze-on.
Published dimensions
| Mount / band size | 28.6 mm (1 1/8 in) seat-tube clamp |
|---|---|
| Designation | 28.6 mm band |
| Typical frames | round steel and older aluminium frames with a 1 1/8 in seat tube at the clamp |
Used on: round steel and older aluminium frames with a 1 1/8 in seat tube at the clamp.
28.6 mm is the smallest of the three common band sizes, sized for a 1 1/8 in round seat tube. Many clamp derailleurs ship as a larger band with shims down to 28.6 mm. Measure the seat-tube outside diameter at the clamp point, because it can differ from the seatpost bore.
Frames and related mount sizes
31.8 mm front-derailleur clamp31.8 mm band34.9 mm front-derailleur clamp34.9 mm bandBraze-on (direct-mount) front derailleurbraze-on tabBSA bottom bracket shellthe frame's other threaded interfaceT47 bottom bracket shellthreaded BB, same frame
SOURCES: BikeRadar, Front derailleurs explained: types, mounts and compatibility · Shimano, SM-AD91 front derailleur clamp band adapter