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 Author | Topic: Intermittant "Scuffing" Noise at Ultegra BB (Read 121 times) |
Eric A
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Karma: 2 |  | Intermittant "Scuffing" Noise at Ultegra BB
« Thread Started on Aug 26, 2009, 3:20pm » | |
Question:
Bike: 2008 Trek 5.2 Madone
What would cause a "paper scuffing against paper" sounding noise? I think it's coming from my bottom brackets dust covers. Not really heard very often, but it's bothersome. I've disassembled the same, cleaned and re-greased everything. Is this related to the torque on the bottom bracket (left-side crank bolt tool)? Or bent dust covers?
Thanks in advance for any advice!
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Eric A
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Karma: 2 | | Re: Intermittant "Scuffing" Noise at Ultegra BB
« Reply #1 on Sept 22, 2009, 8:03am » | |
As it turns out the BB bearings had worn-out. I can rotate either crankarm to the 12:00 position and wiggle it laterally. I had double-checked the pinch bolts and bracket bolt previously. This caused an eccentric pedal revolution as I pedaled. Not sure where the noise was produced out of all this.
Easy fix. I'd rather have the bearings go than any other component.
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DaleP
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Karma: 5 | | Re: Intermittant "Scuffing" Noise at Ultegra BB
« Reply #2 on Sept 26, 2009, 4:27pm » | |
Sept 22, 2009, 8:03am, Eric A wrote:| Not sure where the noise was produced out of all this. |
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At your advanced age, you might check your knees! 
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Eric A
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Karma: 2 | | Re: Intermittant "Scuffing" Noise at Ultegra BB
« Reply #3 on Sept 27, 2009, 6:07pm » | |
 Good grief, no kidding!
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Eric A
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Karma: 2 |  | Re: Intermittant "Scuffing" Noise at Ultegra BB
« Reply #4 on Oct 7, 2009, 8:29am » | |
Apparently, it is Trek's warranty policy to replace only the worst bearing out of the two. I had thought that when replacing bearings, you should replace them as a set. I found this policy odd. Is two bearings really going to break their bank? I examined the old (pulled) bearing, I detected no adverse movement. There was wear on the outer race possibly indicating that the whole bearing was rotating in the cup? This bearing set lasted 5512 miles.
However, I am glad that the BB movement and intermittent noise is gone.
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Wrench Goode
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Karma: 4 | | Re: Intermittant "Scuffing" Noise at Ultegra BB
« Reply #5 on Oct 7, 2009, 4:23pm » | |
You are right, they should have been replaced as a set. Did Trek tell you that or a shop?
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Eric A
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Karma: 2 | | Re: Intermittant "Scuffing" Noise at Ultegra BB
« Reply #6 on Oct 11, 2009, 5:22pm » | |
Oct 7, 2009, 4:23pm, Wrench Goode wrote:| You are right, they should have been replaced as a set. Did Trek tell you that or a shop? |
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Oh this is not cool. The shop told me that this was Trek's policy. Now I have one bearing with 5564 miles on it, the other one with 52.
I not happy about how this problem was solved.
Recommendations?
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Tom M
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Karma: 4 | | Re: Intermittant "Scuffing" Noise at Ultegra BB
« Reply #7 on Oct 11, 2009, 8:50pm » | |
I asked Dave about it. The problem is that your frame's non-driveside bearing socket is a little over spec. The stock-size bearing floats in there. That's why you notice the wear on the outside of the old one, and why it feels just fine as a bearing. It's not worn out, it's just not big enough, like an original piston in a re-bored engine block.
Dave called Josh at Trek for tech advice, and Josh sent a slightly-oversized bearing that's a nice snug fit in your frame's non-driveside socket. This is the reason they only sent one. You wouldn't want to try cramming another oversized bearing into the driveside socket unless it really needs one too.
That's the story as I heard it, anyway... hope it makes a little more sense now. It sounds like you'll need the slightly-oversized bearing on the left side every time you need a new one, so I'll try to find out the part number and get back to you with that.
For peace of mind, you could certainly have the driveside bearing replaced too, so they're both the same age. I'm sure either TWT or NDBS would have one.
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Wrench Goode
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Karma: 4 | | Re: Intermittant "Scuffing" Noise at Ultegra BB
« Reply #8 on Oct 13, 2009, 4:33pm » | |
Eric try again, I was at Whistler!!
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