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Old 08-03-12, 01:02 PM   #1
nrsmd
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Adjusting road bike front dérailleur

Looking at videos, it is still unclear to me how to use the high and low screws adjustment screws for the front road bike derailler. When the chain is on the small cog in front and large cog in rear, how do I position the cage with regards to the chain. They books and videos say to leave 1-2 mm clearance between the cage and chain, but they don't clarify if that tolerance is for inner edge of the cage near the wheel or outer edge of the cage near the pedals.
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Old 08-03-12, 01:04 PM   #2
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Outer cage, 1mm is plenty of clearance
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Old 08-16-12, 04:28 PM   #3
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I have a similar proble with a road bike triple front mech adjustment. I can set the limit screw so that the inner cog travel is restricted fine with a fraction of clearance but when I move the rear mech out to test all the gears it rubs on the outside of the front mech. Basically it seems that there isn't enou room within the confines of the front mech (shimano sora) to take the movement across all nine of the rear sprockets. Is this normal or can I do something about it?

Any help really appreciated folks! It's driving me mad!
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Old 08-16-12, 05:00 PM   #4
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Originally Posted by Eccoboy View Post
I have a similar proble with a road bike triple front mech adjustment. I can set the limit screw so that the inner cog travel is restricted fine with a fraction of clearance but when I move the rear mech out to test all the gears it rubs on the outside of the front mech. Basically it seems that there isn't enou room within the confines of the front mech (shimano sora) to take the movement across all nine of the rear sprockets. Is this normal or can I do something about it?

Any help really appreciated folks! It's driving me mad!
If I understand your situation, you are saying that you have a triple, and you are getting some rubbing when you are in the little/front and little/rear combo.

If so, you are "cross-chaining" which is not recommended since it wears the chain and maybe cogs very quickly. And there is no reason to; you can get the same gearing with the middle chainring, albeit on a different rear cog.

Chart your gears using a gear calculator; I like:
http://home.earthlink.net/~mike.sherman/shift.html

Enter the tooth counts for YOUR bike and the charts will show you how the gearing overlaps between inner, middle and outer chainrings.

-TH
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Old 08-16-12, 08:00 PM   #5
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Originally Posted by Eccoboy View Post
I have a similar proble with a road bike triple front mech adjustment. I can set the limit screw so that the inner cog travel is restricted fine with a fraction of clearance but when I move the rear mech out to test all the gears it rubs on the outside of the front mech. Basically it seems that there isn't enou room within the confines of the front mech (shimano sora) to take the movement across all nine of the rear sprockets. Is this normal or can I do something about it?

Any help really appreciated folks! It's driving me mad!
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Old 08-16-12, 08:06 PM   #6
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Quote:
Originally Posted by Eccoboy View Post
I have a similar proble with a road bike triple front mech adjustment. I can set the limit screw so that the inner cog travel is restricted fine with a fraction of clearance but when I move the rear mech out to test all the gears it rubs on the outside of the front mech. Basically it seems that there isn't enou room within the confines of the front mech (shimano sora) to take the movement across all nine of the rear sprockets. Is this normal or can I do something about it?

Any help really appreciated folks! It's driving me mad!
1. That's often normal (some front derailleur cages are wider and don't have the issue)

2. Most integrated shift levers have a trim option to work around the problem. I grabbed this from a Shimano Sora manual:

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File Type: jpg trim.jpg (44.4 KB, 4 views)
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