BB for a 27 Speed Ultegra Groupset

Rusty Cogs 08

My Cannondale is beginning to creak & groan around the cranks. No amount of tightening has helped. I'm in the market to replace the bottom bracket but my LBS tells me that now Ultegra is working off a 10 ring cassette I'll have to replace mine with either a LX or a Dura Ace, neither of which they have in stock.

I'm a bit clueless when it comes to the range of BB's out there. Would someone be able to direct me to say one on chainreactions that would fit the bill ?

kenmc

i don't see how the number of gears makes a difference; it's more so the length of the axle that's the issue (i.e. the RHS of the axle for a triple would be a bit longer than a double I think). Tiagra comes in a triple range, so a tiagra should fit. Doubt a dura-ace would fit, cos that hasn't been triple for ages (ever?) - but it depends on your pedal fittings (square/isis/octalink etc)

blorg

Dura-Ace was actually available as a triple up to 2008, the option went compact in 2009 with 7900- not that this is particularly relevant.

The key issue really is you need to get a bottom bracket to match your cranks- I can only imagine that where "9 speed" becomes relevant is that 9 speed Ultegra was made with a particular bottom bracket interface (probably Octalink) while 10 speed Ultegra went Hollowtech II. So a "ten speed Ultegra BB" = Hollowtech BB cups, which obviously will not work with your cranks.

Do your cranks look like this? If so you need an Octalink BB, from whatever group is available. As Ken says there may be issues regarding length, I am not sure here so will defer to those who know.

Rusty Cogs 08

Yeah, if memory serves, that's a clean version of what I have (went to check and remembered the bike is in the shop ). So I need an Octolink BB to fit a triple I guess ?

This be her
http://www.cannondale.com/bikes/04/cusa/model-4RR1T.html

Looks like it might have had a 105 BB to begin with.