Chain rub on front derailer?



ecandl

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Sep 20, 2006
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I recently installed a new cassette on my new wheel and replaced my old cassette on my old wheel. All are shimano 10 speed. After messing with the barrel adjuster, the shifting is crisp. The problem is in the two highest gears, the front derailer rubs. Is it okay to simply adjust the front derailer out a couple of mm? I placed the spacers as indicated and don't want to experiment with taking out spacers on the cassette if I don't have to. I am learning to fix my bike and have not done anything on the front derailer yet. Thanks.
 

rparedes

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Jul 21, 2007
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ecandl said:
I recently installed a new cassette on my new wheel and replaced my old cassette on my old wheel. All are shimano 10 speed. After messing with the barrel adjuster, the shifting is crisp. The problem is in the two highest gears, the front derailer rubs. Is it okay to simply adjust the front derailer out a couple of mm? I placed the spacers as indicated and don't want to experiment with taking out spacers on the cassette if I don't have to. I am learning to fix my bike and have not done anything on the front derailer yet. Thanks.
If the rear limits are set, make sure the wheel is set correctly, sometimes when you re-install the wheel is sits slightly off , so make sure it's in there correctly. Did you replace the chain also? if so, the new chain and cassette are slightly wider (minimally speaking) since there is no "wear", the rear drive is a tiny bit wider. You should be able to take chain rub by shifting to the big ring , pedaling with one hand (bike is on stand) and adding more tension on the wire by unscrewing your front barrel adjuster until the chain rub disappears- if there is no more adjustment at the barrel adjuster, undo the wire at the FD attachment clamp, screw the barrel adjuster all the way in, then pull the wire tighter and attach to FD. Go to the park tools web site, repair section, and look under "front der indexing". Read them carefully, step by step.
I just went through this when upgrading my RD, cassette, FD and chain.
 

ecandl

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Sep 20, 2006
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rparedes said:
If the rear limits are set, make sure the wheel is set correctly, sometimes when you re-install the wheel is sits slightly off , so make sure it's in there correctly. Did you replace the chain also? if so, the new chain and cassette are slightly wider (minimally speaking) since there is no "wear", the rear drive is a tiny bit wider. You should be able to take chain rub by shifting to the big ring , pedaling with one hand (bike is on stand) and adding more tension on the wire by unscrewing your front barrel adjuster until the chain rub disappears- if there is no more adjustment at the barrel adjuster, undo the wire at the FD attachment clamp, screw the barrel adjuster all the way in, then pull the wire tighter and attach to FD. Go to the park tools web site, repair section, and look under "front der indexing". Read them carefully, step by step.
I just went through this when upgrading my RD, cassette, FD and chain.[/QUOTE/)

I did replace the chain as well. I can easily ride - just hate the noise of the chain rubbing. I will look at things when I get home. The Park tool website looks very helpful as well. Thanks.
 

rparedes

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Jul 21, 2007
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ecandl said:
rparedes said:
If the rear limits are set, make sure the wheel is set correctly, sometimes when you re-install the wheel is sits slightly off , so make sure it's in there correctly. Did you replace the chain also? if so, the new chain and cassette are slightly wider (minimally speaking) since there is no "wear", the rear drive is a tiny bit wider. You should be able to take chain rub by shifting to the big ring , pedaling with one hand (bike is on stand) and adding more tension on the wire by unscrewing your front barrel adjuster until the chain rub disappears- if there is no more adjustment at the barrel adjuster, undo the wire at the FD attachment clamp, screw the barrel adjuster all the way in, then pull the wire tighter and attach to FD. Go to the park tools web site, repair section, and look under "front der indexing". Read them carefully, step by step.
I just went through this when upgrading my RD, cassette, FD and chain.[/QUOTE/)

I did replace the chain as well. I can easily ride - just hate the noise of the chain rubbing. I will look at things when I get home. The Park tool website looks very helpful as well. Thanks.

One thing that is critical, which I originally missed, is the shifting without using the shifters, only use your hand by pulling on the wire (after you've released the tension on the wire by screwing the barrel adjuster all the way in -clockwise- and the chain is on the small chain-ring). You really have to pull fairly hard to make sure the derailleur is really hitting the limit screws (as you shift up and down) and not being "limited" by the tension on the wire.
 

artemidorus

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Mar 10, 2004
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My FD always rubs in the two highest rear gears. I either shift to the big chainring or use the trim.
 

rparedes

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Jul 21, 2007
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artemidorus said:
My FD always rubs in the two highest rear gears. I either shift to the big chainring or use the trim.

Hmm... mine does not. I have the tension set so that at the outermost cog (10 speed 12-27) and largest chainring (compact 50-34) there is a little less than about 1mm clearance. The same holds for the innermost cog and the small chainring...I have to say that it took me quite a while to get it just right (messing with wire tension and hub spacers)... maybe is a slight difference in the hub width? or chain line?
(I have mavic wheels and hubs, I put in a 1.5mm-1+0.5- hub spacers)
 

Lama

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Oct 18, 2004
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artemidorus said:
My FD always rubs in the two highest rear gears. I either shift to the big chainring or use the trim.
Ditto - this is 'normal'

Though I believe that the new dura ace 7900 series is supposed to completely weed this problem out - zero trimming needed I hear!

but then again this is only for those of us who can afford the D/A:cool:
 
Dec 30, 2007
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Lama said:
Ditto - this is 'normal'

Though I believe that the new dura ace 7900 series is supposed to completely weed this problem out - zero trimming needed I hear!

but then again this is only for those of us who can afford the D/A:cool:

If in the big ring and higher gears(smaller cogs), the chain should not rub on the FD. Ensure when in the small ring and lowest gear(biggest cog), the FD inner cage is very close to the chain. shimano says 0.0 to 0.5mm*touvhing or just about), then when shifting to the big ring and smaller(higher) cogs, the FD will travel far enough to not have the chain rub the FD. Then adjust outer limit screw.

DA, ultegra, 105 FDers, shifters all work the same in this regard.