Mountain Bike Reviews Forum banner
1 - 4 of 4 Posts

·
Registered
Joined
·
75 Posts
Discussion Starter · #1 ·
I'm going to be swapping out some FSA gamma cranks for some XT cranks and need a bottom bracket suggestion.

The Cranks are M-752 XT so I need a comparable bb to go with it. I know 73mm shell width but is there a specific spindle width?

Thanks for the help
 

·
what's that rattle?
Joined
·
324 Posts
Chainline Choices

I had a quick look at the Shimano Techdocs and it looks like the 118mm spindle gives a 50.0mm chainline and the 113mm spindle gives a 47.5mm chainline. Most of the new Hollowtech II cranks put you at 50.0mm by default, although some people here with shifting issues have changed spacers around to bring the chainline in a bit.

Personally, I think my 2007 ML2 shifts best with a 49.0mm chainline. I don't know for sure if 47.5mm is too narrow but my guess is that either BB spindle length will work. In any case, Octalink BBs are pretty inexpensive nowadays so it won't cost a lot to try both to see what shifts better with the rest of your build.
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #4 ·
Thanks for the reply, very helpful. Seems i'll have to do some more calculating before buying.

Cheapest i've been able to find the Shimano ES71 bb was $45, rather not have to buy 2 of them if I don't have to.
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top