help needed front derailleur
03-04-03, 07:47 AM
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help needed front derailleur
I bought a used bike and it came with Shimano RX100 front - rear derailleurs and crank. The previous owner installed Shimano STI shifters. It's not a triple crank, only two.
The problem involves the front derailleur. It doesn't go out far enough to stay on the large chain ring UNLESS you change the initial position by pulling the cage out and then locking the cable in that new position. This "works" except the chain doesn't center under the derailleur cage and there's no "feathering" as there should be with only two rings. The initial position should not be so far inside but can't figure out how to "move" it by any of the screws. The H, L screws don't affect that much difference.
I've tried rotating and changing the height of the derailleur but no-go. My last resort will be taking it to the LBS to either have them try something else or replace it with a derailleur that functions normally there.
The problem involves the front derailleur. It doesn't go out far enough to stay on the large chain ring UNLESS you change the initial position by pulling the cage out and then locking the cable in that new position. This "works" except the chain doesn't center under the derailleur cage and there's no "feathering" as there should be with only two rings. The initial position should not be so far inside but can't figure out how to "move" it by any of the screws. The H, L screws don't affect that much difference.
I've tried rotating and changing the height of the derailleur but no-go. My last resort will be taking it to the LBS to either have them try something else or replace it with a derailleur that functions normally there.
03-04-03, 08:33 AM
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The previous owner installed Shimano STI shifters
Most do have some adjustment at the shifter. Sort of a half "click" will move the front der. only slightly. The purpose I have been told is to allow fairly extreme chain angles between the front and rear without rubbing the sides of the frony der., such as inner chain ring (smaller) and 8,or 9th cog on your cassette.
03-04-03, 10:13 AM
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Thanks. I figured out that one of the screws does set the cage closer to the chain so that it now gets to the outer/larger ring. I was wrong about how I thought it was done before I got it. I guess this is as good as it gets. It should have more play in the extreme inside outside positions though. It has none and practically, if not actually scrapes the cage. I'm going to still tinker with it until I get it as good as it gets. 
03-04-03, 10:26 AM
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I have 105 front and back, so they s/b similar to yours. When you're in the outermost cog rear and inner ring front, where does the inner cage plate sit with respect to the inner side of the chain? It should be very close, with just enough clearance not to touch. You can adjust it with the L screw. If that is set right, the H screw setting will work better.
If it's not a screw issue, then you might need to work on tightening with the barrel adjuster while on the outer ring or with the cable at the pinch bolt while on the inner ring. This way you can fine tune the cage position.
Rich
If it's not a screw issue, then you might need to work on tightening with the barrel adjuster while on the outer ring or with the cable at the pinch bolt while on the inner ring. This way you can fine tune the cage position.
Rich
