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Old 09-23-11, 12:52 AM   #1
jensonly
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Rear index shifting causes me to adjust front shifter

Hi everyone
So I'm a pretty big noob to shifting and gears since most of my bikes have been SS but now I am having a shifting issue. The bike is only a couple months old so I'm sure it's probably due for a little tweaking...

Anyway, the rear is indexed shifting, and I find when Im switching to a couple, but not all of the sprockets, that I have to slightly adjust my shifter up front to keep it quiet. It's just a minor inconvenience but didn't always do this.

I can't figure out if this is a front or rear derailleur issue or both. Is this a common issue for indexed shifting?
would appreciate any input!
Thanks
thanks
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Old 09-23-11, 01:14 AM   #2
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When you say "adjusting the front shifter", do you mean going up (or down) one click on a GripShift type shifter ? Or do you need to adjust the actual cable by spinning the adjusting barrel on the shifter ?

Either way, it could be that your front cable stretched a bit, causing it to leave the derailleur a little lower then where it should be. So I would just turn the barrel out by half-turn increments and see if it helps. Let us know.
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Old 09-23-11, 01:34 AM   #3
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They are barend shifters and so while im riding I just fiddle with the gear lever a little until it seems to be 'in gear'. I am doing this on the front only after i have already shifted to the rear.

do you mean leaving my front derailleur a little lower than it should be?
thanks
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Old 09-23-11, 01:52 AM   #4
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Oh I see. Wasn't sure about your shifter type. So if your front shifter is not indexed, then yes, it's normal to have to fine tune it while riding.
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Old 09-23-11, 06:47 AM   #5
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Originally Posted by JeanSeb View Post
Oh I see. Wasn't sure about your shifter type. So if your front shifter is not indexed, then yes, it's normal to have to fine tune it while riding.
+1 Yes, it's perfectly normal, and it's referred to as "trimming." What happens is that as your chain moves across the cogs on the rear wheel, its angle in relation to the front derailleur changes. This can cause the chain to rub on the derailleur cage. Tends to occur when the chain is on the inner or outer cog(s) rather than in the middle of the cassette/freewheel, for obvious reasons.

What confuses me is why this should be happening now, when it wasn't happening before. If your front shifter were indexed, I'd agree with JeanSeb that the cable had likely stretched and the indexing was a bit off. But if your front shifter is friction, that wouldn't cause a problem. Have you done anything that has altered your chainline? Or the angle of the front derailleur cage? If your chainline is right and the FD cage is properly aligned, then I'm not sure what else to suggest.
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Old 09-23-11, 07:06 AM   #6
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Trimming is indeed a normal requirement and is not limited to index rear shifting. Even indexed front shifters offer a second position (or more) for the front derailleur cage over the chain as the rear cogs are changed. If you are "cross chaining", i.e. using the smallest cog or two with the small chainring or the largest cog or two with the big chainring, then trimming is certainly necessary.
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Old 09-23-11, 04:56 PM   #7
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thanks for the suggestions everybody. Guess it's seems like it's a common thing and just a minor annoyance. but since it's friction in the front I think i'll jsut make sure the cage is aligned anyhow. Probably should adjust things a bit anyway as they haven't been since i got the bike a couple of months ago
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