BB and crankset compatibility

Quoted post said:

Originally posted by davebee
I am currently looking to upgrade an old mountain bike which has a half decent aluminium frame but has only been fitted with an acera groupset up to shimano LX, to use as my bumming around bike.

My main query is this. How do i tell what kind of bottom bracket I have and how do I know if it will be compatible with an LX chainset?

Also I was wondering how easy it is to remove my old cranks and BB, because this is something I have never had to do before. I know that I need a specialist tool but am at a total loss as to which tool i will need to
a) remove my particular set of cranks (dunno what they are sorry, but seem to have a bolt type thingy beneath the dust cap and thats as far as i have got)

and

b) to remove the bottom bracket.


thanks for your help

An old Acera crank BB will not be compatible with a new lx crankset that uses a splined BB. Even an older lx crank that uses a tapered spindle may require a different length than what you have in the bike.Buy the Zinn maintenance book or check the repair section at www.parktool.com for answers to the rest of it.

Quoted post said:

Originally posted by davebee
I am currently looking to upgrade an old mountain bike which has a half decent aluminium frame but has only been fitted with an acera groupset up to shimano LX, to use as my bumming around bike.

My main query is this. How do i tell what kind of bottom bracket I have and how do I know if it will be compatible with an LX chainset?

Also I was wondering how easy it is to remove my old cranks and BB, because this is something I have never had to do before. I know that I need a specialist tool but am at a total loss as to which tool i will need to
a) remove my particular set of cranks (dunno what they are sorry, but seem to have a bolt type thingy beneath the dust cap and thats as far as i have got)

and

b) to remove the bottom bracket.


thanks for your help

Go to the site the OP mentions at URL:
http://www.parktool.com/repair_help/FAQindex.shtml
Once there, scroll down to the illustration of the bicycle and place your cursor over the center of the crank where the annotation will read "bottom bracket"; and there you can read about bottom bracket + tools and techniques. Then continue scrolling to the section about "Crankarm and Pedal"
You will see another section that describes the tool(s) and techniques you will need to pull the crankarms off the bottom bracket.
As the OP mentioned, there are square and Octalink Bottom Brackets Spindle ends. You will see what you have now. New LX level and above have Octalink.

cheers folks