Bicycle Mechanics - Bottom Bracket Compatibility

I know this thread has been done before but I couldn't find exactly what I needed so sorry :o

Anyway, I currently have an FSA RPM crankset with an FSA ISIS Cartridge BB (standard BB on a felt 45 if that helps) ... Anyway my chainring really needs to go and looking at replacements I don't know how to distinguish what cranksets will be compatible with my current BB ... can someone explain the basics of the BB (different' threads, what "cups" are etc...) ... or at least let me know what BB's would be compatible

I'm interested getting a crankset similar to this

http://www.performancebike.com/shop/profile.cfm?SKU=2371

but I don't know if I'd need to replace the BB as well

Thanks!

I know this thread has been done before but I couldn't find exactly what I needed so sorry :o

Anyway, I currently have an FSA RPM crankset with an FSA ISIS Cartridge BB (standard BB on a felt 45 if that helps) ... Anyway my chainring really needs to go and looking at replacements I don't know how to distinguish what cranksets will be compatible with my current BB ... can someone explain the basics of the BB (different' threads, what "cups" are etc...) ... or at least let me know what BB's would be compatible

I'm interested getting a crankset similar to this

http://www.performancebike.com/shop/profile.cfm?SKU=2371

but I don't know if I'd need to replace the BB as well


You do, the ISIS spline pattern is different from Shimanos.

Threading of the frame won't be an issue. All recent bikes that weren't made in Italy use the same ISO threading.

See: http://sheldonbrown.com/bbsize for details

Sheldon "Interchangeability" Brown

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Thanks for the help sheldon ... I couldn't justify spending the extra money to replace a perfeclty good BB/crank arms so I just got a new chainring instead! :)

Hopefully your new ring shifts well.

Lifeforms ... used to listen to that a lot about 10 years back.

Indeed! ... It makes me feel old realizing how long ago I started listening to FSOL