Bottom Bracket Options

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Shimano Press-fit

Sleeve option - #ISMFCM970P


New Press-fit Bottom bracket from shimano. Dura-Ace. SM-FC7800-P. Retail, about $30 a set.

Shimano's new press fit BB will allow for a bunch more options with bottom bracket widths and walls.

Dura-Ace. SM-FC7800-P

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/BB/EV-SM-BB91-2987_v1_m56577569830682102.pdf

  • SM-BB91-41A, MTB, Sealed, I-SMBB9141A
  • SM-BB91-41B, RD, Sealed, I-SMBB9141B
  • SM-BB91-42A, Unsealed, I-SMBB9142A


xtr - SM-FCM970 PRESS FIT w/ inner cover dura-ace - SM-FC7800 PRESS FIT

Allows for full carbon bottom bracket shells.

Wider shell spacing for improved suspension designs.

press releases say that scott has exclusive rights in the first year, but we all know how the bike industry really works. Yeti already has show bikes with it. The AS-R.

Press-fit-bb-1.jpg
Press-fit-bb-2.jpg
Press-fit-bb-3.jpg
Press-fit-bb-4.jpg

Shell Design

  • Road, 86.5mm shell (symetrical)
  • MTB, 92mm shell (offset 2.5mm on drive side)

or

  • MTB, 89.5mm shell with a 2.5mm spacer on right side

If the shell is not sealed, an inner cover is needed:

  • Road, FC-7800 Inner Cover
  • MTB, FC-M960 Inner Cover

The inside of the shell needs a 41mm diameter 9.3mm deep ream on each side.

Reaming and Facing the Shell

I need to order a 1.625" reamer from KBC ($140.10)

Once that comes in, it will be reground to 41mm at: Pacific Reamer & Cutter Service
4115 Broadway
Oakland, CA 94611
(510) 654-1844

Expensive? Yes.


Pics

Hollowtech2-shell-4.jpg

Hollowtech2-shell-5.jpg

Hollowtech2-shell-1.jpg

Hollowtech2-shell-2.jpg

Hollowtech2-shell-3.jpg

Other Systems

http://www.velonews.com/article/85518