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Discussion Starter · #1 ·
so i've removed my bottom bracket and it turned out to be a shimano bb-es70 with 73 marked underneath.

its off a cannondale full suspension frame that is supposed to have 68mm bottom brackets but i'm assuming the 73 on the bb itself means the frame bb threads have been tapped out to clean up the old threads?

also the drive side crank has a bit of wiggle when inserted onto the splines.

is any amount of wiggle acceptable? the non drive crank arm is pretty solid on either end of the bb so i've isolated the crankarm keyways to be the issue.

if i need to replace can i use any octalink or ultrega 1 crankarm?
 

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Discussion Starter · #2 ·
or can i install a self extracting type bolt with threads on the collar and inside to reinforce the center of the crankarm on the octalink splines?
 

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Never trust a fart
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68 or 73 means the width of the BB shell. Not the diameter of the threads.

If there is wiggle when the crank arm retaining bolt is tightened down to proper torque specs, then you have one of two problems.

Problem one is that the BB is toast - bearings are sloppy. A new BB will solve this

Problem two is that the crank arm to BB interface is wallowed out. It will continue to wobble until a new crank arm/bb is installed.

If you can find a single crank arm without damaged splines, then go for it. But usually the drive side crank arms are virtually impossible to find by itself, and then you are regulated to purchasing an entire crank set.
 

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Discussion Starter · #4 ·
hrmm i cant find specs on the year 2000 version of this model but 99 and 98 list 68.

is it possible to fit a 73 bb in the shell of a 68 frame? was working fine in the bike i took for a ride or two since purchasing in 2008.

also any insight on buying a set of self extracting bolts for the crank arm and using them to reinforce the center of the crank arm?

i have already isolated that it is the driver side crank arm with slightly worn splines.

p.s. i found sheldon browns online bb guide and identified this as a v2 octalink type bb.
 

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Never trust a fart
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Yes, you can install a 73mm BB in a 68mm frame. Its done all the time with the new outboard bearing cranks. To make up for the 5mm in difference, spacers are added to get the BB cups to the desired width.
 

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Discussion Starter · #6 ·
without spacers what issue will i run into?

i measured and the frame i just took this 72mm bb out of has a 68mm shell.

no spacers noticed, maybe a custom outer cup was used? she was cinched up nice and tight and like i said rolled smooth for a few good rides before pulling and still spins nice.
 

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Never trust a fart
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The 73mm BB is incorrect then. Both cups should be flush with the frame.

Without spacers (depending on the BB if they are needed or not), the BB will move in the frame and could damage the threads on the shell.

Since the BB shell is 68mm, you need a 68mm bottom bracket with the appropriate spindle length to match what you have.
 
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