Bicycle Mechanics - Front Derailler Adjusting Help!

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View Full Version : Front Derailler Adjusting Help!


Portis
03-17-04, 03:11 PM
I am having trouble getting my front derailler adjusted. I have consulted the Park Tool website and followed their instructions. I have the chain on the innermost chainring and sprocket. There is NO tension on the cable. The derailler is resting agains the seat tube.

So obviously I can't set the Low limit screw to allow it to go farther inward. Again, the front derailler is resting on the seat tube, there is no tension on it.

I have attached a picture. What am i missing?


Portis
03-17-04, 03:15 PM
My other bike looks like this, with the chain in inner most position.

Retro Grouch
03-17-04, 03:55 PM
I am having trouble getting my front derailler adjusted. I have consulted the Park Tool website and followed their instructions. I have the chain on the innermost chainring and sprocket. There is NO tension on the cable. The derailler is resting agains the seat tube.

So obviously I can't set the Low limit screw to allow it to go farther inward. Again, the front derailler is resting on the seat tube, there is no tension on it.

I have attached a picture. What am i missing?

It looks to me like you have quite a bit of angle in your derailleur cage. What happens if you rotate it on the seat tube so that the cage is parallel with the big chain ring?


Portis
03-17-04, 05:36 PM
I rotated it and i think it helped. I got everything working on the L side and then ran into trouble on the H side. I am fairly new to this and it seems like this front Derailler doesn't have enough travel to it. I always have rubbing in the extreme innermost and outermost chainring rear sprocket combinations. I am learning. Slowly. :rolleyes:

randya
03-17-04, 08:18 PM
You need a longer axle!!! (to move all three chain rings further out from yer seatpost)

Retro Grouch
03-19-04, 10:01 AM
I rotated it and i think it helped. I got everything working on the L side and then ran into trouble on the H side. I am fairly new to this and it seems like this front Derailler doesn't have enough travel to it. I always have rubbing in the extreme innermost and outermost chainring rear sprocket combinations. I am learning. Slowly. :rolleyes:

Chain rubbing on the extreme crossover combinations isn't unusual. Now that you've gotten this far, try this procedure exactly.

1. Disconnect the shift cable from the front derailleur.
2. Adjust the position of the derailleur on your seat tube. The outer derailleur cage should be parallel to the big chainring and the outer cage should just miss the big ring by about 2mm when you push it outward with your finger. You may have to raise the derailleur a bit to keep the inner cage from hitting the middle ring.
3. Set the low gear limit screw. One of the adjustment screws on top of the derailleur will move the cage inward or outward. put the chain on your smallest chainring and the biggest cog in the back. Now adjust that screw until the inner cage just misses the chain by 1mm.
4. Connect the shift cable. Pull the cable just taut with needle nose pliers. Make sure that you go the correct way around the anchor bolt, usually over the top.
5. Adjust the cable tension. Try all the various gear combinations. A little rub in the extreme crossover gears is OK. It may be necessary in your case to unscrew the other limit screw on top of your derailleur to get the travel you need.
6. Set the high gear limit screw. Shift into the big chainring, small rear cog combination. Fiddle with the other screw on top of the serailleur until the outer cage misses the chain by about 1mm.

If this doesn't work, post again. I'll get you back on the road.

Portis
03-20-04, 09:41 AM
I did what you suggested. It seemed to work pretty well. However I am still getting some slight rubbing when the chain is on the innermost cog/chainring and when the chain is on the outermost cog/chainring. I am not talking about when the chain is on the innermost cog and outermost ring. Again, it is when it is in the positions where you are to set the limit screws, the extreme outermost and innermost, respectively.

In the pic below the chain is in the proper position for setting the L limit stop. I think my cage is still out of parallel but it is not as bad as the picture makes it look. I think that is the only other option though is to keep tweaking the cage alignment.

I have moved it a bunch of times but can't seem to get it right. The chain clears fine everywhere except where i mentioned.

Retro Grouch
03-20-04, 01:02 PM
OK, you're getting there, now try this:

I realize that it can be a pain to get the derailleur aligned perfectly using the clamp. Now that you've gotten it this close, try sticking your biggest screwdriver into the cage from the back and gently bend it into submission.

Aren't you glad that rear derailleurs aren't this touchy to adjust?