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Discussion Starter #1
It's the first time I'm buying a whole bike as separate parts on my own... and of course as a newbie I'm paying the bitter price . :madman:

I bought a Cannondale Flash Carbon frame with BB30 hole and and Shimano XTR crank Fc-m980 which later I found out it's BB90. ............... Again :madman:

So, what should I do now?

1) Install an adapter/converter (adding 50g) to use the XTR? (cheaper option)

2) Buy a Cannondale SL Hollowgram / Truvativ and sell the XTR? (expensive option)

3) ?


ps: I live in S. America, so I took months importing all parts... sadly it's not like go to the LBS and exchange cranks....
 

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Nothing about that crank is BB90, that designation refers to the BB/frame interface. The cheapest option and the route I would go is to instal a BB30 adaptor into the frame. They come in two styles one that has threads so you can use a normal english threaded BB. And one that has bearings so you can press in a 24mm ID bearing for use with your Shimano cranks.
 

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Discussion Starter #3
Nothing about that crank is BB90, that designation refers to the BB/frame interface. The cheapest option and the route I would go is to instal a BB30 adaptor into the frame. They come in two styles one that has threads so you can use a normal english threaded BB. And one that has bearings so you can press in a 24mm ID bearing for use with your Shimano cranks.
Thanks!

Performance wise, is there any disadvantage in use the adapter?

What do you say about this one:2012 Wheels Mfg BB30 Adapter for Shimano - Competitive Cyclist
 

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That's a great solution provided the BB30 bearings are already pressed into your frame.

Disadvantages, probably not the Shimano cranks are top of the line in my book so you get a better crankset to work with your frame. You pick up some weight in the delrin adaptor but it's not going to be much. I doubt you pt out enough power to overwhelm the stiffness of a XTR crank either.
 

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Can someone tell me the true diffentance between the BB30 Bottom Bracket and the BB90 bottom bracket.
BB30 uses a 30 mm crank spindle. BB 90 is actually a trek specific fitment. BB86 is the Shimano version. Either one of them are both intended to be used with 24mm crank spindles. Or 22/24 spindles in the case of Sram GXP fitments. All of these setups are designed to remove threaded BB shells in frames, which makes them easier to manufacture.
 
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