I have an SE Draft and I need to replace the Bottom Bracket. I want to buy this Bottom Bracket at a local bike shop and it is a Shimano BB54 and its 68mm by 107mm and I found out my bikes crank holds a Euro Catridge BB so can this type of bottom bracket go into my bike?
Euro is the term to differentiate between the much larger American size bottom bracket for one-piece cranks on most BMX bikes. The American bottom bracket is a press-in fitting with threads to adjust and secure it on the arms, where the euro bottom bracket is smaller and has threads on the frame where the cups screw into. There's a Euro adapter which is a pair of aluminum disks that press into the American bottom bracket and secured with 3 or 4 long bolts joining the two, and is threaded on the inner circle to accept Euro (really English-threaded) bottom-bracket cups, and YES, they will take the bottom bracket you're describing. The 'cartridge' part is really describing the bearings, the bottom bracket bearings are two self-contained bearings, like in rollerblade or skateboard wheels, just larger. It's all a one-piece unit with adjustable cups. Older bottom brackets had loose ball bearings you had to set in grease in cups while you were installing. Outdated but still in wide use on inexpensive bikes. Here's a good resource to give you an idea:
