68-118mm now I get a bit confused. I get the 68mm bit but is the 118mm the axle or shell length ?
axle.
Yep its the axle.
68mm is the shell length, it's a function of the frame. (can also be 73mm)
118mm is the axle length and is a function of the chainset. They generally vary from 107mm - 121mm, with a few exceptions.
thank you. have just replaced octalink bb on my inbred with bb some one gave me. its 68-118 and now the front deralleur wont line up in the granny ring. I ride an inbred. The only other size a seem to be able to find is 121, will the 3 mm make that much difference?
have a look on the park tools site - there's good instructions on adjusting the front deraileur.
What size was the bb that came off - was probably 113 I'd imagine?
Could be anything, some were 121, Deore M530 were IIRC. Exactly which chainset is it?
You shouldn't need to adjust your front mech after changing the BB, that means you've put a different length it. 3mm difference will definitely screw it up.
lx hollow tech with xt front and rear mechs older 9 speed. going to dig the old one out the bin in a min. The bike is one of the original geared frame inbreds.
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Like this one? Apparently it's 113-118, but using a 118 would suggest it would be less likely to reach the big ring. If it won't reach the granny, 121 sounds like the best bet.
Any reason you can't measure the BB that did work!?
Surprised it didn't work as front mechs are fairly adaptable to different axle sizes. 3mm difference is only 1.5mm on either side. FWIW I use a 118mm square taper axle on my 853 Inbred as recommended by Brant for a 50mm chainline.
Sure you don't just need to adjust the low/high screws and tweak the cable adjust on the front mech/shifter?
Aye thats the one. Just been through the wheelie bin and it is a 121. I am a muppet. I adjusted the mech to no avail. Usualy pretty good with these things and I built the bike up from scratch, just a bit forgetful at times.
There were two models of LX on octalink BB. The original one like njee posted ran shorter BB axles. Then there was the later bulbous arm style that ran much longer axles. I would imagine you have one of these instead?
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Now i look at them they are the later bulbous ones. aint it amazing the difference 3mm can make. really skint so was trying to avoid buying a bb but £10 on crc I can't complain.
I was looking for a photo of those, couldn't find one!
