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PostPosted: Sun Aug 11, 2013 5:48 am 
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Joined: Tue May 20, 2008 5:34 am
Posts: 80
Has anyone else noticed that their Shimano 6770 rear derailleur upper pulley has quite a bit of drag? Ironically, I only noticed this after 4K miles. The lower pulley spins super smooth. I guess I'm used to older Shimano rear derailleurs. Or is there an issue? Thanks!

-Pete


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PostPosted: Sun Aug 11, 2013 6:50 am 
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Joined: Tue Jun 12, 2012 4:40 pm
Posts: 161
I have a 6770 rear mech sat next to me on my desk and the upper is certainly not as free spinning as the lower.


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PostPosted: Sun Aug 11, 2013 8:24 am 
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Joined: Thu Nov 29, 2012 12:36 pm
Posts: 240
Location: The Netherlands
Yep. that's how it is..

The upper pulley has 'sealed' bearings, which means that they've placed two small rubber rings on each side of the pulley. These things cause looooottss of drag. And as the removal of these rubber rings will result in play on the pulley, I would suggest just to buy some aftermarket ones.


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PostPosted: Sun Aug 11, 2013 11:23 am 
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Joined: Wed Dec 14, 2011 8:20 pm
Posts: 214
A dip on chain lubricant makes it a little better, but yes, it still drags quite a lot. In terms of watts, it isn't something significant.

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PostPosted: Mon Aug 12, 2013 10:47 am 
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Joined: Thu May 27, 2010 2:36 pm
Posts: 30
After a winter of cycling with grits and salt on the road my upper pulley almost did not turn, but the lower was smooth.

Turns out the upper pulley is a bushing, and only the lower is ball bearing.

Just change it out for a ball bearing pulley and it will get a lot better.


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