Indexing on front derailleur

[BLACKvoodoo]

I have taken a spacer out of the right side ( chain ring side ) of my crank assembly, I accidently put it in but my Bb shell is 75mm and the spacer was for a 68mm. When It was in I sent it to the bike shop to set the indexing, but then after removing the spacer ,naturally the chain rings will be 5mm closer to the shell so my front derailleur is not laying directly over the chain rings when I change gears.

 

I can take it back to have set but I would like to know how to do it myself.

It's an XT groupset , IF it makes a difference.

[zaslinger]

Search youtube - Pictures are worth a thousand words.

 

But my limited understanding is:

 

Align the front DR parallel to the chain rings.

Adjust the height so that the DR just clears the big (outside) chainring.

Adjust the DR indexing screw so that the DR does not pull the chain off the chainrings either inside or outside.

Adjust the cable at the DR.

Fine tune everything with the barrel adjuster on the shifter.

Edited November 8, 2011 by zaslinger

[BLACKvoodoo]

I thought the small screws were only to set your top and bottom limits

[Captain Fastbastard Mayhem]

Correct - but your limits would have changed with the removal of the spacer!

 

Set the limits, and then adjust the barrel adjuster by your shifter until it tracks perfectly. If your derailleur doesn't GO to the bottom because the cable is limiting it, loosen the nut that clamps the cable to the derailleur and set it so that, at the cable's slackest setting, the derailleur is at the bottom of the stroke. Then re-tighten, and set up the limiting screws, then set the indexing by way of the barrel adjuster.

 

It really is simple to do, once you've done it once...

[BLACKvoodoo]

Thanks Guys, I'll do that tonight. Any excuse to fiddle in the garage.

[zaslinger]

Are you still talking about adjusting your gears?!?!

 

"Fiddle in the garage"

 

You weren't perhaps that oke on the cape town beach the other day were you?

[David Marshall]

I find the following easiest.

1) Release the cable before you set the lo limit screw. Set the low limit with the chain on largest sprocket at the back and smallest in the front. The chain must just clear the inside of the FD cage.

 

2) Connect the cable without any slack but not tight enough to move the FD off the lower limit setting.

 

3) Change to the smallest sprocket at the back and by pulling on the FD cable with your hand (between the guides on the downtube) change to the largest chain ring on the crank. Adjust the Hi set screw so that the chain just clears the derailleur cage while on the large ring (keep the cable tight while setting).

 

4) Release the cable and the chain will again move to the small chain ring. If you have three rings on the crank, use the shifter to move the chain to the mid ring.

 

5) Now shift through the full range of the rear sprockets and see that the chain does not contact the cage. If it does adjust the cable tension with the adjuster until it just clears. Once this is done the other rings normally don't need further adjustment.

 

6) If your crank only has two rings, I set the screws as above and then adjust the tension to clear the FD while on the large ring. Then check the small one. Just be careful of not making the cable too tight otherwise it will prevent the FD reaching the low limit setting. Hope this helps.