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Crank arm play, what should I do?

Old 12-20-19, 09:09 PM
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ssonny
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Crank arm play, what should I do?

This'll be my first fixed gear build, so i apologize in advance if my obliviousness is insufferable. But basically, i've finished installing everything except my crankset, its on the bike, but the crank arm is wobbling an awful lot no matter how hard i crank that thing down. Im wondering if i should get some spacers, or if im just not installing something correctly?

Bottom bracket shell is 68mm
Bottom bracket: SRAM GXP's
Crankset: SRAM Omniums

video showcasing wobble: imgurcomf26nppn (couldnt post links so i improvised, im sorry. Dot between imgur and con, and slash between com and f26nppn)

Last edited by ssonny; 12-20-19 at 09:12 PM.
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Old 12-20-19, 09:54 PM
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Did you add the wave washer?
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Old 12-20-19, 09:54 PM
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Originally Posted by ssonny View Post
This'll be my first fixed gear build, so i apologize in advance if my obliviousness is insufferable. But basically, i've finished installing everything except my crankset, its on the bike, but the crank arm is wobbling an awful lot no matter how hard i crank that thing down. Im wondering if i should get some spacers, or if im just not installing something correctly?

Bottom bracket shell is 68mm
Bottom bracket: SRAM GXP's
Crankset: SRAM Omniums

video showcasing wobble: imgurcomf26nppn (couldnt post links so i improvised, im sorry. Dot between imgur and con, and slash between com and f26nppn)
And what torque reading are you hitting? If you aren't using a torque wrench, then you almost certainly aren't torquing it enough.
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Old 12-21-19, 04:53 AM
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dsaul
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I'm fairly certain that you have forgotten to put the non-drive side spacer/dust cover on (part #1 in the image) before installing the crank arm. Without that part, the crank arm will always be loose.
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Old 12-21-19, 09:23 AM
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ssonny
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Originally Posted by dsaul View Post
I'm fairly certain that you have forgotten to put the non-drive side spacer/dust cover on (part #1 in the image) before installing the crank arm. Without that part, the crank arm will always be loose.
unfortunately, i have. i might just try installing 2.5 spacers on either side and see how that works out.
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Old 12-21-19, 09:33 AM
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Originally Posted by ssonny View Post
This'll be my first fixed gear build, so i apologize in advance if my obliviousness is insufferable. But basically, i've finished installing everything except my crankset, its on the bike, but the crank arm is wobbling an awful lot no matter how hard i crank that thing down. Im wondering if i should get some spacers, or if im just not installing something correctly?

Bottom bracket shell is 68mm
Bottom bracket: SRAM GXP's
Crankset: SRAM Omniums

video showcasing wobble: imgurcomf26nppn (couldnt post links so i improvised, im sorry. Dot between imgur and con, and slash between com and f26nppn)
Where exactly is the play/wobble?

What is moving relative to what? How much play/wobble in mm? What orientation is the motion?

What exactly are you "cranking down"?
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Old 12-21-19, 09:52 AM
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I just watched your video and that's not supposed to happen. Something is wrong with the non drive side bearing/cup assembly. It looks like someone installed a drive side bearing in the non-drive side. The drive side has a 24mm internal diameter and the non-drive is 22mm. Is this brand new?

With GXP, the non drive bearing is captured between the crankarm and a shoulder on the spindle. There should not be any movement in the direction your video shows, even without the drive side cup installed, so spacers are not the problem.
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Old 12-21-19, 09:59 AM
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Originally Posted by dsaul View Post
I just watched your video and that's not supposed to happen. Something is wrong with the non drive side bearing/cup assembly. It looks like someone installed a drive side bearing in the non-drive side. The drive side has a 24mm internal diameter and the non-drive is 22mm. Is this brand new?

With GXP, the non drive bearing is captured between the crankarm and a shoulder on the spindle. There should not be any movement in the direction your video shows, even without the drive side cup installed, so spacers are not the problem.
Yeah its brand new, so basically.. i installed it wrong. Im stupid, sorry for the trouble. 🤦‍♂️

Last edited by ssonny; 12-21-19 at 10:04 AM.
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Old 12-21-19, 10:03 AM
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Originally Posted by ssonny View Post
Yeah its brand new, so basically.. i installed it wrong. Im stupid, sorry for the trouble. 🤦‍♂️
No need to apologize. That's what this forum is for. Obviously you weren't the only person ever to do this either.
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Old 12-21-19, 10:21 AM
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Originally Posted by ssonny View Post
Yeah its brand new, so basically.. i installed it wrong. Im stupid, sorry for the trouble. 🤦‍♂️
I doubt that you installed the cups on the wrong side. They are threaded opposite of each other and would have been very difficult to install on the wrong side. If the bearing is wrong, it happened at the factory.
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Old 12-21-19, 10:31 AM
  #11  
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bearing/

appears the crankarm is secure.what I see is the bearing OD moving.with the arm removed will the bearing fall out or feel loose? maybe a counterfeit crankset with low quality BB?
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Old 12-21-19, 10:43 AM
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Originally Posted by dsaul View Post
I doubt that you installed the cups on the wrong side. They are threaded opposite of each other and would have been very difficult to install on the wrong side. If the bearing is wrong, it happened at the factory.
Should I buy a new bb? Or is there anything I could do?
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Old 12-21-19, 11:01 AM
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Your earlier post mentioned that you hadn't installed the dustcap/washer part. Do you still have this? It's kind of necessary.

If not, you can buy a kit with the proper washers from Amazon:
https://www.amazon.com/Bottom-Bracke...s%2C137&sr=8-4

Of course, check to ensure that this kit matches up properly with your BB. If you can't find a match, I think the BB itself is around 30-40 bucks.

Last edited by WizardOfBoz; 12-21-19 at 11:05 AM.
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Old 12-21-19, 12:06 PM
  #14  
'02 nrs
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Originally Posted by ssonny View Post
Should I buy a new bb? Or is there anything I could do?
confirm a bad non drive bearing/cup then try to return it if you bought it new from a dealer/bikeshop.
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Old 12-21-19, 09:49 PM
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ssonny
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Originally Posted by '02 nrs View Post
confirm a bad non drive bearing/cup then try to return it if you bought it new from a dealer/bikeshop.
how should i determine whether or not the bearing/cup is bad or not?
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