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Old 08-05-09, 11:23 AM   #1
wunderkind
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Adjusting front derailleur

So I've swapped out my cranks and chain rings from another bike successfully (after I figured out that there is a difference b/t ISIS and Tapered Square!!).
Anyhoo, had to adjust the front derailleur cage now that it has to fit over a larger set of chain rings. My problem lies with, I seem to be able to set it to change b/t the 2nd and largest ring. But it just won't go down to the granny ring. I've fiddled with it for >2hrs.
Each time I manage to get it to switch from one ring to the other, the other one will not work.
Here's the procedure that I gathered from the many DIY videos.

- Set chain to largest rear cog against smallest chainring. Adjust height of derailler cage to make sure it can go past the largest chain ring.
- adjust Low limit.
- Tighten the shifter cable
- Set chain to smallest rear cog against largest chainring... but cage just won't want to move to largest chain ring!
- Tried releasing the tension of the cable, but it goes nuts thereafter.

So right now, I just adjust the derailleur to work with the middle and largest chainring. Granny ring is not possible. Please help!
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Old 08-05-09, 11:27 AM   #2
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Did your original crank have a triple chainring? If so, we can assume that your new crank sits outside the "inner" range of the DR which was set up for the old one.
It's likely possible to adjust the "low" limit screw to get sufficient movement, but I'm wondering about your overall chainline situation.
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Old 08-05-09, 11:51 AM   #3
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You are at your travel limits of the derailleur it seems to me. To find out, release the cable altogether. Set your high and low adjust screws to the limits of their travel (meaning, you are not contacting them at all). With your hand manually move the derailleur back and forth to observe the range of travel available. If it is not greater than the width of your triple the FD is the problem. Only cure for that is to replace it with one that has a wider capacity.
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Old 08-05-09, 11:52 AM   #4
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Originally Posted by Bikewer View Post
Did your original crank have a triple chainring? If so, we can assume that your new crank sits outside the "inner" range of the DR which was set up for the old one.
It's likely possible to adjust the "low" limit screw to get sufficient movement, but I'm wondering about your overall chainline situation.
I don't get it.
Yes it had triple chainring.
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Old 08-05-09, 12:25 PM   #5
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Originally Posted by DIYGUY View Post
You are at your travel limits of the derailleur it seems to me. To find out, release the cable altogether. Set your high and low adjust screws to the limits of their travel (meaning, you are not contacting them at all). With your hand manually move the derailleur back and forth to observe the range of travel available. If it is not greater than the width of your triple the FD is the problem. Only cure for that is to replace it with one that has a wider capacity.
Hmm... I did that and it can travel back and forth b/t the range of the chainrings. Could it be the angle? I its a ****mano SiS after all.
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Old 08-05-09, 04:19 PM   #6
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For just about any FD problems - re-installation is the best fix. The questions about FD problems are so common here that I bothered to Copy & Paste the following. Pass it on as wished:


Take the cable off the FD. Now install it from scratch as per Park Tool Repair:

http://www.parktool.com/repair/readhowto.asp?id=75

And BicycleTutor:

http://bicycletutor.com/adjust-front-derailer/

When you have it properly trimmed and are ready for the cable - a new one wouldn't hurt - you want to pull the cable taut - not too tight, taut. Then apply 48 to 60 inch-pounds to the pinch-bolt. Then put it through it's paces.

It's always easier and faster to install a FD from square-one, than it is to make adjustments with it already attached. This tends to fix one thing - while throwing another out of kilter. Start fresh. You'll get it.

Adding a barrel-adjuster can solve many problems with the cable coming loose - or being too tight.
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Old 08-05-09, 10:03 PM   #7
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Those are the instructions that I have gone through already!

Anyways, just an update. After dinner today. I readjusted the FD cage again. Long story short, it is fixed! I wish this process is like computers where I can "Save" the setting! Also an "Undo" command would've saved me some time too. I am so happy and proud of myself! This is my first attempt. Feels like Rocky! Heck I felt so good I decided to work on the other bike which I swapped out the parts with. That one was easy. Took me no more than 10 minutes. All done!
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Old 08-05-09, 11:24 PM   #8
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Was the FD-cage too high? Or was the outer-cage not properly parallel? What did you do?

(sorry for trying to make your problem vanish...LOL)
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Old 08-06-09, 12:30 AM   #9
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To be quite honest, I don't know exactly what I did because I made so many cumulative adjustments and then all of a sudden... voila! It just shifted through the chainrings happily. I think I had to experiment with different heights for the cage and I guess I finally found one.
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