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Barrell adjuster - question

freshefreshe Posts: 63
edited June 2013 in MTB workshop & tech
Hi folks,

Im playing around with my RD and I have a question reg the initial position of the barrell adjuster. Just wanted to ask here first before just trying it.

When installing the shifting cable its advised that the barrell adjuster is screwed all way in. No I think if I keep my barrel lets say 2 full turns away from that limit it should allow me to adjust the position of the derailler cage in both directions, as in my case I feel it could do a tiny adjustment but the barrell is all way in.

What do you think?

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    the barrel adjuster is not for adjusting position. it is for setting tension. position is set by the lower stop screw.

    try reading the set up info on parktools.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • owenlarsowenlars Posts: 719
    Start with it half way in (or out depending on how you look at life) as you can then tighten or loosen the cable when you do the final indexing after you have installed it. I suggest you read Park Tools, as Nicklouse says, to get the drift before you get in too deep, although to be fair,once grasped, indexing is pretty simple.
  • cooldadcooldad Posts: 32,904
    Loosening the cable will (or should) make no difference - read Nick's post above.
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  • owenlarsowenlars Posts: 719
    Depends whether freshe's problem is indexing, in which case use barrel adjusters, or the starting position of the derailleur in which case use the limit screws. I just said if I was installing a cable (which it seems freshe is doing) I would start with the barrel adjuster half way in to give me the maximum indexing adjustment.
  • freshefreshe Posts: 63
    Owenlars - you are correct. Adjusting the barrell moves the derailleurs cage and forces the chain to go up to latger sprocket. It seems in my case that i could use that tiny bit of adjustment the other way but my barrell is screwed all way in (as per the installation guides). Thats why I asked if this is something that i could try. Limit screwes work only on the edging sprockets anyway.
  • nicklousenicklouse Posts: 81,520 Lives Here
    freshe wrote:
    Owenlars - you are correct. Adjusting the barrell moves the derailleurs cage and forces the chain to go up to latger sprocket. It seems in my case that i could use that tiny bit of adjustment the other way but my barrell is screwed all way in (as per the installation guides). Thats why I asked if this is something that i could try. Limit screwes work only on the edging sprockets anyway.
    no dont do it. yes it moves it but that is only as you are adding tension to the inner.

    set the lower position with the stop. fit the cable and then adjust the tension to get the shifting correct then set the top stop screw.

    do not use the barrel adjuster to set the position.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • owenlarsowenlars Posts: 719
    Nicklouse is correct. Set the stops, put the cable on, give it a good tug to stretch the cable a bit and then reset tension by loosening where it is fixed to the derailleur pulling the cable through the bolt and re tightening the cable fixing bolt, then index with barrel adjusters. Read the Park Tool instructions.

    The way to think about it is the cable moves the derailleur but the stops define where the movement starts and ends and also stop you running the chain off the cassette. It all has to be right to work.
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