Originally Posted by
HillRider
Recent Shimano square taper and Octalink bottom brackets use an 8 mm Allen wrench for the fixing bolts. Older shimano, and most other Japanese square taper bottom brackets (SR. Suguino, Sun Tour) use a 14 mm hex bolt.
Just to complicate things, Campagnolo used a 7mm Allen on the Victory cranks, and prior to the mid 80s most high-end cranks (Campy, Shimano, Sugino, TA, Sakae Ringyo) used 15mm bolts; only low end models used 14mm bolts. Stronglight and Zeus were the notable exceptions, using 16mm bolts.