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Shimano BB Crank compatibility

Posted: Tue Nov 05, 2013 6:34 pm
by Oswald
A couple of questions here :-)

I have a BMC GF01 with a BB86 Ultegra bottem bracket.
Can I replace this with a BB91 Dura Ace bottem bracket? (Can get my hands on one at a good price)
Can I replace my Ultegra cranks with Dura Ace 7900 or 9000 using the BB86 Ultegra or BB91 Dura Ace bottem bracket?
Can I use a Dura Ace 9000 crankset with a Dura Ace 7900 group? So will the 10 speed KMC chain and DA 7900 front mech work with the 11 speed DA chainrings?
Is the crankset for a SM-BB7900 different then the crankset for a SM-BB86 Press Fit?

Thx

Re: Shimano BB Crank compatibility

Posted: Tue Nov 05, 2013 7:13 pm
by btompkins0112
1. Yes, BB86 and 91 are the same
2. Both
3. Yes, the 10-speed chain will function fine.
4. No, all Shimano Hollowtech II cranks have the same spindle diameter/length.

:beerchug:

Re: Shimano BB Crank compatibility

Posted: Tue Nov 05, 2013 7:58 pm
by Oswald
Cool, thx !!

Re: Shimano BB Crank compatibility

Posted: Mon Nov 11, 2013 11:43 am
by Oswald
If I buy a crankset online, is the Crank Arm Fixing Bolt included with it? I mean the big center bolt that attaches the left crank arm to the axle?
I may have found a buyer for my crankset, but am not sure if I should also give him the bolt. Don't want to end up buying a new crankset online and then having to place a new order for a bolt... Also, is there a difference between the Dura Ace 7900 and Ultegra 6800 bolts? I'm not talking about weight, just need to find out if they are interchangable.

Thx!

Re: Shimano BB Crank compatibility

Posted: Mon Nov 11, 2013 12:17 pm
by MajorMantra
Yes, it's included, there's no reason to separate the bolt from the crank. Note that it doesn't hold the left crank on, it exists ONLY as a bearing preload. The pinch bolts hold the left crank arm on.

Oh, and a shameless plug, I wrote a post answering your original question in some detail: http://thesetbackpost.com/mechanics/shi ... of-things/

Re: Shimano BB Crank compatibility

Posted: Mon Nov 11, 2013 12:34 pm
by Oswald
Thx :-)