How do I figure out what size Bottom Bracket I need?
 

Hi, I am building up a road frame, and I need to know what size Bottom Bracket I need to order. Im building a 2003 Orbea Mitis road frame. The cups are 68mm and the threads are english. I have no idea what length spindle I need. Ill be building with a double ring Ultegra crank. I tried emailing Orbea, but had no luck there. Roadbikereview was useless so far. Can anybody help me here? Hopefully somebody knows what size I need. If now, how do i measure it. Thanks
-Bill

Most double cranks take a 107 to 110 mm spindle... Sheldon Brown has the data at http://sheldonbrown.com/bbsize.html#ultegra

Looks like for a 1998-2004 Ultegra double, you need a 110 mm Octalink V1 spindle. But if you use a 2005 or 2006 crank set, it has an integrated BB spindle and you just need to buy the bearing cups.

The size is most likely stamped on the side of the cartridge. Take it off and look at it.

If it's Octalink Ultegra you'll need a 68 x 109.5 BB, either BB5500 or BB6500.