This special external BB for BMX cranks is compatible with all MTB frames with threaded bottom brackets (Euro BB). This solution allows for the use of more durable Spanish BB sealed bearings in external BB cups.
-compatible with 19mm crank axles
-external aluminium cups with two big & strong Spanish BB sealed bearings
-compatible with all MTB frames with 68mm Euro BB & 73mm Euro BB (two sets of central spacers included)