# Shimano BB-9000 Bottom Bracket backwards compatible?



## jta (Jun 27, 2012)

Anybody know if the new DA 9000 bottom bracket can be used with DA7900, Ultegra 6700 or 105 5700 Hollowtech II cranksets? Thanks.


----------



## ms6073 (Jul 7, 2005)

The DA 9000 crankset has a 24mm diameter spindle (BSA24) so there should be no reason for it not to be backwards compatible.


----------



## woz (Dec 26, 2005)

Yes there are no changes to the bb standard for 9000.


----------



## jta (Jun 27, 2012)

Thanks for the info guys. It looks like a good choice then, given it's price point. 80 grams, and claimed 50% reduction in drag on the seals. Should fit the bill.


----------



## StillKeen (Oct 4, 2005)

I read (can't remember where) that the splines on the outside have a smaller PCD. So you get a small plastic splined shim to go between your existing BB install tool and the cups to install.

I like this because:

1) I don't have to buy a new tool
2) The plastic will stop the metal tool from marking the splines on the cups like the current ones do (yes, I can be careful, but always seem to get a few little marks, particularly when removing and reinstalling the cups).

I'll be going to the DA-9000 cups (Thanks woz for confirming that they fit) as soon as my stash of DA-7800 and 7900 cups are used up. Be interesting to see if the bearing life suffers from the new seals and smaller balls (?).


----------



## jta (Jun 27, 2012)

Just picked up the new bottom bracket from R&A cycles (who were great about checking with the Shimano rep to confirm compatibility). 

The cups are noticeably smaller than my current bottom bracket, and weighed in at 65 grams (I even checked my scale's accuracy by weighing a roll of nickels - it's spot on). Will be installing the bottom bracket with a new Ultegra 6750 compact crankset and a dura ace chain as part of a drivetrain upgrade. If anyone expresses interest, I'll report back on installation or performance.


----------



## aclinjury (Sep 12, 2011)

report back please


----------



## jta (Jun 27, 2012)

acl, installation of the bottom bracket, cranks and chain was really simple - this coming from someone who's never done this before. Oddly enough, the chain was the most complicated task. Dropped 140 grams from moving/drive components and shortened the crankarms by 5mm. I was able to manage a very short test ride, but all the combined changes do seem to make a significant difference. Cranks spin really nice and smooth. Shorter crank arms will help with pedal stroke/cadence. Knees are happy. Overall, bike seems more responsive and no more toe overlap. Glad I did it.

Let me know if you have any specific questions.


----------



## geo3 (Feb 19, 2005)

jta, were you able to use the new 9000 chain with the 6750 Crank?


----------



## jta (Jun 27, 2012)

geo3 said:


> jta, were you able to use the new 9000 chain with the 6750 Crank?


hi geo, if you are looking to replace your chain running the 6750 crank you need to use the 10 speed Dura Ace CN-7900 or CN-7901 chain. (Or, other compatible 10 speed chain)

The new Dura Ace 9000 chain is for 11 speed and narrower from my understanding - not compatible. 

Edit: I used the DA-7901 and like how the bike's running with all the other upgrades I mentioned. Not sure if you'll notice a difference if the only thing you are replacing is the chain.


----------



## geo3 (Feb 19, 2005)

Thanks for the update on the chain choice you made. I have Ultegra Di2 with an old FSA crank. I am upgrading to an Ultegra Crank and wanted to start with the best new chain I could fit.


----------



## jta (Jun 27, 2012)

I swapped out an FSA Gossamer crankset on my bike - the improvement in shifting is remarkable on a mechanical set-up. I can imagine you would have really smooth and reliable shifting with Di2/Ultegra/DA. Good luck, I'm pretty sure you'll like the results.


----------

