Shimano BB Crank compatibility

Discuss light weight issues concerning road bikes & parts.
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Oswald
Posts: 792
Joined: Thu Jan 08, 2004 10:11 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

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btompkins0112
Posts: 2693
Joined: Fri Feb 11, 2011 3:04 am
Location: Mississippi

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:

by Weenie


Oswald
Posts: 792
Joined: Thu Jan 08, 2004 10:11 pm

by Oswald

Cool, thx !!

Oswald
Posts: 792
Joined: Thu Jan 08, 2004 10:11 pm

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!

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MajorMantra
Posts: 293
Joined: Mon Nov 02, 2009 8:38 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/

Oswald
Posts: 792
Joined: Thu Jan 08, 2004 10:11 pm

by Oswald

Thx :-)

by Weenie


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