I would like to change the chainring on my Trek Earl to a 46 or possibly a 48 and change the crank also. Anybody know what type and size (square, splined) of BB is installed at the factory? I was looking at the Omnium or the Sugino 75 cranks. There isn't much in the way of specifics on Trek's website or in the manual.
Last edited by oneidabow1; 06-03-14 at 11:14 AM.
Reason: additional words
EAI Bare Knuckle / Leader 725 / 1975 Raleigh Professional Track
Considering your two choices, it doesn't matter what length or type spindle your current BB has.
If you get Omniums, they don't use a traditional spindle and include a GXP BB specific to that crank. If you choose Sugino 75s you will need to use a BB having a 109mm ISO spindle, which I am 100% certain your stock BB does not have.