Braze-on (direct-mount) front derailleur (braze-on tab)
Which frames use a braze-on tab front-derailleur mount, and how to tell band from braze-on.
Published dimensions
| Mount / band size | no clamp, bolts to a frame tab |
|---|---|
| Designation | braze-on tab |
| Typical frames | carbon and higher-end aluminium road, gravel and MTB frames with a moulded or welded derailleur tab |
Used on: carbon and higher-end aluminium road, gravel and MTB frames with a moulded or welded derailleur tab.
A braze-on (direct-mount) front derailleur has no band; it bolts to a tab on the frame. If your frame has a tab, buy the braze-on derailleur, not a clamp version. A clamp adapter such as the Shimano SM-AD91 lets a braze-on derailleur fit a round tube if the frame has no tab.
Frames and related mount sizes
Front derailleur mount on a Trek Emonda SLR (2024 on)braze-on tabFront derailleur mount on a Specialized Tarmac SL8 (2024 on)braze-on tabFront derailleur mount on a Canyon Ultimate CF (2020 on)braze-on tab28.6 mm front-derailleur clamp28.6 mm band31.8 mm front-derailleur clamp31.8 mm bandBSA bottom bracket shellthe frame's other threaded interface
SOURCES: BikeRadar, Front derailleurs explained: types, mounts and compatibility · Shimano, SM-AD91 front derailleur clamp band adapter