Bicycle Mechanics - coda crank bottom bracket interface

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isotopesope
09-23-06, 12:43 AM
hello. this is my first time posting in this forum... anyways, i've come to a dilemma that i thought someone might have an answer to, because i have no idea at this point.

i have some coda mountain bike cranks that i have no idea what sort of bottom bracket they require. i blindly assumed they required an isis bb... so i install a isis bb into the bike and go to put the cranks on, and there is no way they're going to fit. weird. so i peer inside and see 8 slots in the interface of the crank, and think it's an octalink... well, it's not fitting onto an octalink bb i have laying around either. i measured one of the splines on the octalink spindle and am reading it to be 3mm at the base. when i measure one of the slots on the crank itself, i read it is 2mm wide. what the heck sort of bb do these fit on? any ideas? i know good ol' cannondale love making proprietary parts, so is this what i'm running into here? i don't know much about these cranks; i accquired them from a friend who found them laying around a shop he had worked in. they're 5 bolt, 94 bcd, and the spider is removeable like those truvativ stylo's from awhile back.

ideas? suggestions? file 13?

thanks,
chris

seely
09-23-06, 04:55 AM
There are two standards to Octalink. Not 100% sure this is the answer as I am not 100% sure what the difference is, but there is an Octalink V1 and V2 standard. I know the lenght of the interface is difference but not sure on the spacing.
isotopesope
09-23-06, 02:46 PM
huh. that sounds vaguely familiar. the bb i'm using is a newer 105... the measurements i took are of the thickness of each spline... each octalink spline is too fat to fit in the slots on the cranks. i think these cranks might find themselves in the bottomless parts bin. dammit.

isotopesope
09-25-06, 12:05 PM
bump. anyone?
HillRider
09-25-06, 02:47 PM
Your 105 Octalink is a "road" pattern bb and I'm almost certain what you need is an MTB patern Octalink as used on previous generation XT, LX, etc. bottom brackets.

Octalink bbs all have eight splines (obvious huh?) but the length and height are different between road and MTB designs and they are not interchangable. BTW, ISIS bb's have 10 splines.
isotopesope
09-25-06, 08:22 PM
Your 105 Octalink is a "road" pattern bb and I'm almost certain what you need is an MTB patern Octalink as used on previous generation XT, LX, etc. bottom brackets.

Octalink bbs all have eight splines (obvious huh?) but the length and height are different between road and MTB designs and they are not interchangable. BTW, ISIS bb's have 10 splines.
ah! i didn't realize the road and mtn octalink pattern were different. i know isis is 10, i just ASSumed, since it wasn't a shimano crank, and i had the isis and 105 bb's floating around so tried both.

thanks!
tomacropod
09-25-06, 10:06 PM
um, coda also had their own splined pattern a few years ago. Completely proprietary, but revolutionary in how it preceded modern splined designs (talking modern here, not 1940s designs). I don't know much about it except the cranks were marketed as "magic motorcycle" cranks in their road incarnation.

- joel
isotopesope
09-26-06, 11:35 AM
um, coda also had their own splined pattern a few years ago. Completely proprietary, but revolutionary in how it preceded modern splined designs (talking modern here, not 1940s designs). I don't know much about it except the cranks were marketed as "magic motorcycle" cranks in their road incarnation.

- joel
hmm... interesting. good ol' cannondale. ha! these cranks are definitely mountain cranks though.

after hillrider's suggestion, i dug deeper into my parts bins and found an older 105 octalink bb. it had more narrow splines than the newer 105 bb i was trying. i then dusted off my geared hardtail and pulled off the lx cranks. the lx octalink bb fits these cranks perfectly. problem solved!

thanks again for all the help!
tomacropod
09-26-06, 07:02 PM
excellent news. CODA made their weird cranks primarily for their high end mtbs though, with 29/42t chainrings. But if you really had some of those I would suggest selling them on ebay as they fetch quite a penny!

- Joel
TallRider
09-26-06, 07:37 PM
Here's an image from Sheldon's site showing the differences between 2 octalink standards. Bummer that you bought an ISIS BB and installed it before realizing.
http://www.sheldonbrown.com/images/bbsx3labeled.jpg