Bicycle Mechanics - Indexing and the Front Derailleur

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View Full Version : Indexing and the Front Derailleur


FatBomber
01-19-04, 12:10 PM
I have a new bike and it has a double chainring setup in the front. I was doing some minor adjustments to it and I noticed that when shifting from the small to the large ring, it takes two "clicks" to shift. The same applies to go from the large to the small ring. One click moves it about half way from one to the other.

My question is this:

Do I need to adjust my cables to get the indexing right? If so, how is this accomplished? My high and low limits are set perfect right now.

Merci


Zeltar
01-19-04, 12:35 PM
I have a new bike and it has a double chainring setup in the front. I was doing some minor adjustments to it and I noticed that when shifting from the small to the large ring, it takes two "clicks" to shift. The same applies to go from the large to the small ring. One click moves it about half way from one to the other.

My question is this:

Do I need to adjust my cables to get the indexing right? If so, how is this accomplished? My high and low limits are set perfect right now.

Merci


Yes, then indexing is adjusted by the cable tension. Once you have the upper and lower limits set it is a matter of getting the cable tensioned correctly. If you are installing new cables, you will probably need to adjust again to compensate for the stretching once the cables get broken in.

It is also a good idea to have the cranks going at the same cadence you would be riding at. If you get good shifting at a low cadence on the stand and then take it our for a ride, it might not shift as well. Just from my personal expierence.

Good luck.

Ebbtide
01-19-04, 01:52 PM
It is also a good idea to have the cranks going at the same cadence you would be riding at.

It makes me angry when I don't think things like that. It certainly seems to be good info to have, thanks!


OneTinSloth
01-19-04, 04:04 PM
one of the two clicks could be the trim adjustment. say you're riding on the inner ring up front and the outermost cog in the rear, the chaint might hit the front derailluer, so you'd just do one click to get the derailluer out of the way. same thing if you're using the big ring and largest (innermost) cog in the rear.if the cahin starts rubbing, you adjust the FD accordingly. of course, you could eliminate all this hassle by jsut getting a single speed, but...well, that's not for everyone. :)

tommy2pants
01-19-04, 04:06 PM
Yes, then indexing is adjusted by the cable tension. Once you have the upper and lower limits set it is a matter of getting the cable tensioned correctly. If you are installing new cables, you will probably need to adjust again to compensate for the stretching once the cables get broken in.

It is also a good idea to have the cranks going at the same cadence you would be riding at. If you get good shifting at a low cadence on the stand and then take it our for a ride, it might not shift as well. Just from my personal expierence.

Good luck.That may just not be right.I suspect one of each of the clicks is the trim function in the shifter.

tommy2pants
01-19-04, 04:08 PM
It is also a good idea to have the cranks going at the same cadence you would be riding at.

Good luck.Cadence is crank revolutions per interval of time.

Don Cook
01-20-04, 01:54 PM
I have a new bike and it has a double chainring setup in the front. I was doing some minor adjustments to it and I noticed that when shifting from the small to the large ring, it takes two "clicks" to shift. The same applies to go from the large to the small ring. One click moves it about half way from one to the other.

My question is this:

Do I need to adjust my cables to get the indexing right? If so, how is this accomplished? My high and low limits are set perfect right now.

Merci

Would you confirm that what you're talking about is an STI type indexed shifting on a FRONT derailluer that has only two chainrings? And that the front derailluer shifter clearly has three positions?

FatBomber
01-20-04, 01:56 PM
Sure seems that way to me. I tightened the cable and it seems to be operating much better.

tommy2pants
01-20-04, 02:06 PM
Sure seems that way to me. I tightened the cable and it seems to be operating much better. www.parktool.com has the complete drill on FD adjustment.Start at the BEGINNING and do it right. Your shifters if shimano also have have 'half clicks' when in both the big and small ring positions that are trim functions for the FD.

FatBomber
01-20-04, 02:10 PM
I did all that and it was after that I found the "doubleclick". I believe that I neglected to re-tension the cable after adjusting. Seems okay now, but I plan on riding it and shifting it to get some stretch on the cables.