You can purchase clamps to convert a braze on style derailleur into a clamp mounted derailleur.
What does braze on front derailleur mean.
Braze on an alternative to the clamp is the braze on derailleur hanger where the derailleur is mounted by bolting a tab on the derailleur to a corresponding tab on the frame s seat tube.
There are really only two types of.
There are two types of road front mech mounting.
Band or braze on.
There are really only two types of road front derailleur mount and the band clamp type is becoming less common as the braze on can be bolted up to fit anything.
This avoids any clamp size issues but requires either a frame with the appropriate braze on or an adapter clamp that simulates a braze on derailleur tab.
There are two band sizes 31 8mm or 34 9mm so check current model or frame manufacturer s recommendations.
Braze on some frames have a front derailleur mount integrated with the seat tube and do not require a clamp those are called braze on front derailleurs.