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Which barrel adjuster to adjust: shifter or derailleur?

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Which barrel adjuster to adjust: shifter or derailleur?

Old 07-25-20, 12:40 PM
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poorbikedude
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Which barrel adjuster to adjust: shifter or derailleur?

The gears on my 18 speed MTB are not shifting smoothly. The high and low limits on the derailleur have been set and there is no "b" screw. I have a barrel adjuster on the shifter and a barrel adjuster on the derailleur. Which one do I use to make adjustments or do I use both? If both, how do I do this so as to avoid canceling out adjustments? Any help would be appreciated.
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Old 07-25-20, 12:47 PM
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Steve B.
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Assuming you are having issues with the chain on the cassette.

Rear for permanent, front for on-the-fly is my work method, but they both do the same thing.

If the chain is having trouble getting up to a larger cog, turn the rear barrel adjuster counter-clockwise as you look at the adjuster from behind. If the chain is slow getting to a smaller cog, go clockwise. Baby steps, 1/4-1/2 turn at a time then try it.
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Old 07-25-20, 12:50 PM
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Is the direction for barrel adjustments the same whether the barrel is on the shifter or the derailleur?
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Old 07-25-20, 12:54 PM
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dsaul
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Both do the same thing, which is effectively make the cable housing longer or shorter. Clockwise will make the housing shorter(move the derailleur toward the smaller cogs) and counterclockwise makes the housing longer(moves the derailleur toward the larger cogs).
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Old 07-25-20, 01:01 PM
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Thank you. I will give it a try.
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Old 07-25-20, 01:09 PM
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Originally Posted by dsaul View Post
Both do the same thing, which is effectively make the cable housing longer or shorter. Clockwise will make the housing shorter(move the derailleur toward the smaller cogs) and counterclockwise makes the housing longer(moves the derailleur toward the larger cogs).
Thank you for not saying (incorrectly) that the adjustments "add" or "remove" tension, as is so often done. The derailleur spring provides the tension, the adjustments change the indexing by changing the effective length of the housing and thus the cable.
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Old 07-25-20, 01:36 PM
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Bike on the repair stand, off the ground , the fine tuning to get the index shifting in sync ,

It is easier to do with the rear adjuster, because I can watch what it does.. as I turn it..
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Old 07-25-20, 08:11 PM
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Old 07-25-20, 11:33 PM
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Originally Posted by poorbikedude View Post
The gears on my 18 speed MTB are not shifting smoothly. The high and low limits on the derailleur have been set and there is no "b" screw. I have a barrel adjuster on the shifter and a barrel adjuster on the derailleur. Which one do I use to make adjustments or do I use both? If both, how do I do this so as to avoid canceling out adjustments? Any help would be appreciated.
What works well for me is this:
I make sure that the front barrel adjuster (when it exists) is screwed out (from the completely screwed in position) for at least one full turn.
The basic idea is to allow for some (fine) adjustments while sitting on a bike - it's more convenient.

Apart from that, it doesn't really matter which one you use for tuning. I usually make tunning on the rear one, just making sure that the front one is done as explained above.

Another thing:
Cables tend to elongate a bit over time, and cut their way in the housing. It's minute if tuned properly at the start, but generally: in the future, you are a lot more likely to be turning the adjustment barrel(s) out, over time, than screw them in.
So I make sure that there is at least two full turns of "room" for turning them out, without risking them being completely screwed out. Hope I explained well what I mean.
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