Anyone have any idea what the axle length might be for my old Octalink bottom bracket?

The play that it has is starting to bang like a shit house door so I suppose it needs replacing.

I know, I could always take it out and read what it says but tbh, these are a pain in the arse to remove ime so I’d rather only take it out when I’m putting the new one in.

Its a 68mm BB shell and an XT crankset FWIW. Anyone know where I might find this out?

Chances are it will be 113mm most octolink xt crank setups I have come across is 113. If not that and if the crank arm looks very close to the bb body then it’s a 110mm

If you google search for si followed by the number off the back of the arm
You should get the shimano service instructions listing the bb length

Eg si fcm 760

I have a spare deore octalijk bb that might do you.

email in profile if interested .

IIRC, most Octalink BBs had a 113mm axle length BUT there were 2 variants – later versions had longer splines to try to resolve issues with cranks working loose and coming off.

I only found this out when trying to replace an LX Octalink BB, but a part number should resolve it for you.

If you know the shell size the only other relevant dimension’s the axle length. Can’t you just take the cranks off & measure it ?

Just make sure you get an mountain bike octalalink and not a road one as they won’t work

Oh and xtr will not work with anything but xtr cranks

There was no 110mm version. It was 113 and 118 then later some craziness with 121 and 126. It really is the easist way to take it out and read what it says on it.

If we’re talking mountain bike Octalink 113mm gave a 47.5mm chainline and 118mm gave a 50mm chainline (which I have on my bike). Some LX chainsets required an oddly sized 121mm axle to give the appropriate chainline.

Check SheldonBrown, probably 113 or 118 for XT Octalink.

http://sheldonbrown.com/bbsize.html

CRC still do these at good prices.

PaulD

Thanks for all the replies.
It seems the best way of finding out the correct size would be to just remove the existing and have a look but in my lazyness, I was hoping to avoid.
I’ve got a distant memory of it being a 113mm but it’s being in there that long I can’t be sure – lets hope the threads haven’t seized!!

assuming that your xt cranks are 9 sp then you might need a 122/26 bb

i recently replaced my 9sp deore cranks with alivio 8 sp ones.

thought i could keep existing octalink 68 bb…not

had to replace the 126 unit with a 113 or summit.

so i guess 9 sp=wider chainline

probly best to remove that old bb first then

hope that helps 🙂