crank differences

[ablister]

hi, please can someone tell me the differences between the crank BB sizes. USA, Euro, mid etc and how do i know what i have?

thanks, ali

[selfpreservation]

new school bikes tend to have euro bb old school usually have US bb you can tell by looking a US bb is about 2 inches diameter and a euro is 19mm 3/4 an inch so its pretty easy to tell , also mongoose bb have a different thread to standard bb/cranks

[ablister]

thanks 

[MeddlE]

US BB have press in cups, Euro has smaller screw in cups, mid has no cups as the bearings press straight into the frame.

[brass monkey!]

New School BB's are also the same size as Mountain Bike BB's - so I believe !