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Quick BB question(5 posts)

Quick BB questioncyclejim
Jun 10, 2002 9:01 PM
I just took a quick look at BBs online and noticed that most do not list a shell width. Is there a most common shell width? The frame I bought says it requires a 70mm Italian thread bb. Is 70mm the standard or does it just depend on manufacturer.

Second part of question- do I need to run a BB made by the same company as my gruppo? Or can I mix and match?
re: Quick BB questionGuru_at_AmClassic
Jun 11, 2002 2:45 AM
There really is no "standard" bottom bracket size. The most common is 68 and 73 which are English in size. The 70mm is Italian. For your bike, you need a 70mm by __mm. The remaining size is based on what crank type you have. The spindle length and type of taper is important and yes, you can mix and match to a point. Find out what length in recommended by the manufacturer and see what they have to offer first. If you are running a Campy crank, as of right now, they are the only ones making a taper to fit their cranks. If it is Race Face, Shimano or someone elses, you will be ok because they use a 2 degree taper. Hope that helps.

American Classic
re: Thanks...can I also ask whycyclejim
Jun 11, 2002 5:52 AM
The spindle length is not selectable when I put a BB in my cart at some sites? Are they assuming that I will be running a double or a triple?

Take Shimano BBs for example- I can get the Ultegra as a 68mm or 70mm, with a spindle length of 109.5 or 118.5mm. I need the 109.5 for a double or the 118.5 for a triple- wouldnt this be something obvious I need to pick when purchasing?
re: Quick BB questionOld_school_nik
Jun 11, 2002 2:48 AM

Here is a link for all your BB needs. Yes 70 mm is standard (italian).

Compatability is VERY important - not he width of the shell bu the taper of the spindle, although the length of the spindle is important too - best to use the same manufacturer for crank and bb - unless the bb specifies which cranks it works with - for example, old Campy bb and older shimano spindles (not splined) will not work together - whereas current chorus and record with with chorus and record cranksets.
re: Thanks....cyclejim
Jun 11, 2002 5:53 AM
for the link, Sheldon Browns site is great. I found the answer to my stem question there also!