Originally Posted by
Chriscraft760
JohnDThompson, I read somewhere that the Trek Investment Cast BB's were made in two configurations and the 60TSI being more scarce than the 58TSI. Can you tell me why the two different angles in BB? Which is better?
The numbers indicate the angle between the seat tube and down tube; TSI was the initials of the designer, Tim Isaac. Only the larger frame sizes (60cm and higher, IIRC) required the 60° shell; the majority of frames used the 58° shell simply because that's what comprised the majority of demand in frame sizes.