Octalink/Hollowtech Help!

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Hey folks - I'm trying to use an M751 LX chainset on a current build, it uses a funny BB, all a bit modern for me. Can anyone help with the correct one I need? I think it's an octalink one I need, but the cranks say hollowtech on them. It's the year that LX went bluey/grey with the finish.
Can anyone shed any light?
It's being fitted into a 2000/2001 FSR with a bottom bracket mounted front mech.
 
Hello 👋🏻

LX was denoted 570 I believe, anyway the es51 was the octalink bottom bracket model to match the LX cranks. Whatever the modern day equivalent is will not be as long lasting if the un300 is anything to go by (modern version of the square taper un51).

 
If you are running an etype front mech there were BBS designed for this, though I think you can drop a spacer depending on the width of your frames BB shell.

Search the web for Sheldon brown bottom bracket and you should find a page that lists almost every crank and it's designed BB length.

I had this set up on a bike, remember buying the wrong BB, something in my head recalls needing quite a long one for some reason, 122? Or maybe that was the wrong one?
 
yeah, and if you are searching and then think,oooh lets get something a bit fancier, look for octalink version 2. version 1 is only for XTR and durace/ultegra/105 road stuff...version 2 is for all other mtb.

and octalink is the bottom splined bracket (but not the same as ISIS), and hollowtech is the crank arms (hollow alluminium arms)
 
FC-M751 (or M571, specs identical)

ES70 was the 'spec', but any the same will do.

For BB mounted front mech, you'll need the 'E' version.
( BB-ES70E)

If it's a
73mm shell width, then a 118mm length is needed, for a
68mm shell width, then a 113mm length is needed.
for the 'E' spec setup.

No need for Sheldon when the specs are here on the SI-F650D document.

Get whatever you can grab.
 

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