# Ultegra SM-BB6700 Bottom Bracket choice



## winstonw (Apr 27, 2011)

I've got a 2010 Trek Madone 4.7 with full Ultegra Groupset. 
I want to replace the bb. The component is SM-BB6700 

However, there's a choice:
(a) Shell width 68mm, Thread dimensions 1.37x24 TPI
(b) Shell width 70mm, Thread dimensions M36x24 TPI

How do I tell which is right? 

Further, is there another BB tool available apart from Shimano TL-FC32/36? 

Any advice about removal and installation heads ups much appreciated.


----------



## brucew (Jun 3, 2006)

winstonw said:


> (a) Shell width 68mm, Thread dimensions 1.37x24 TPI
> (b) Shell width 70mm, Thread dimensions M36x24 TPI


A) English
B) Italian

To the best of my knowledge, Trek has never used Italian. Go with A.

I use the Park Tool BBT-9.


----------



## winstonw (Apr 27, 2011)

Thanks very much Bruce. Can I ask how you torque the BB up appropriately?


----------



## MisterMike (Aug 12, 2004)

Agreed with winstonw, it's likely choice A. 
If I understand you correctly you already have a BB6700 and want something different. If so the 6700 already has the thread marked on it on one of the external cups similar to the picture below. As for tools there are plenty. I use the Park BBT-9 too.


----------



## winstonw (Apr 27, 2011)

Thanks MM. I am at work currently and hadn't looked closely enough at the BB on the weekend to specifically note all the external markings. 

The bike came with a 6700 BB and am wanting to replace with same after a very wet year of heavy wear.


----------



## winstonw (Apr 27, 2011)

OK, presume all 16 notch bottom brackets are the same dimensions. 
So guess these tools should be ok with a 3/8" torque wrench. 


Park Tool BBT-19

Pedro's External Bearing BB Tool


----------



## DaveT (Feb 12, 2004)

winstonw said:


> Thanks very much Bruce. Can I ask how you torque the BB up appropriately?


The bottom bracket will come with instructions and torque values. Pretty easy to do.


----------

