The bicycle drive unit 1, wherein {HEAD ~ the detent plate} 16 is machined into {TAIL ~ the rotary plate} 5 with a plurality of detent grooves 16 a included therein, 
The bicycle drive unit 1 , wherein { HEAD ~ the detent plate } 16 is machined into { TAIL ~ the rotary plate } 5 with a plurality of detent grooves 16 a included therein ,
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH