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I've been trying to straighten out some shifting issues on a kid's bike, it's a Diamondback and is a few years old. On the front gear-set it has a few issues that I am having trouble fixing through l and h screw adjustment and indexing.

  • When shifting from the small ring to the middle it doesn't always make the shift, I have to twist it a little past the audible click to ensure a shift.

  • Also it's shifting into the big ring way too early. When moving the shifter about halfway to the audible click it's already moved over, letting go at this point results in a downshift.

From what I'm interpreting fixing one of these issues would make the other worse. Does anyone have some tips?

  • The problem you describe sounds plausible for a lower end group-set on a kids bike. Is the faster shifting into the big ring really a problem? Can the shifter not be just moved until it clicks? – Argenti Apparatus Feb 11 '18 at 2:27
  • Having worked on a diamondback in the past, its pretty much the definition of cheap BSO. Do you have gripshifters or driction thumb shifters or indexed shifters or pod shifters? – Criggie Feb 11 '18 at 3:32
  • Also, your limit screw adjustment might be a bit early. You want to get the shifter placing the chain right first, and then worry about limiting it's movement after that. The initial adjust should be length of inner cable. – Criggie Feb 11 '18 at 3:34
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    @Criggie Its got gripshifter's, and ill redo my limit screws and indexing. – HyperSlayer72 Feb 11 '18 at 3:54
  • @ArgentiApparatus The shifting into the big ring is not the main issue, its the up-shift into the middle. I just wanted to provide all the info I could. – HyperSlayer72 Feb 11 '18 at 3:57
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On the shifter handle, get the adjustment nut all the way in(where cable connects to the handle). Now get yourself some new brake outer and inner cable. Lube it very well, with oil(not grease, nor WD-40)

Now for derailleur, one screw is for the lower limit, the other one is for the upper limit. This is to ensure that the chain will not go out of the gears

Now shift into the lower gear, and fix the cable on the derailleur as tight as you can but without moving the derailleur. Once this is done you just need to use the adjustment nuts on the handle or the derailleur. I like adjusting it from the derailleur as the first fine tunning and any other from the handle, so I can keep track of how much wear the cables have.

Also check out if the derailleur is straight and parallel to the chain rings. If it's not, it will not shift properly.

  • Personally I do it the other order - I get the chain shifting right and then tweak the limit screws. If the chain falls off while doing the first bit its no big deal because the transmission is not under load. – Criggie Feb 13 '18 at 20:38
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    All modern brake cable is teflon lined and does not require lubing. Adding a lubricant can have the opposite effect. – Criggie Feb 13 '18 at 20:39
  • @Criggie Never had an issue using teflon lined sheats(pigtail and stright cable made) with lube. I've learned this from my local bike shop. Other technique is to set the lower limit a little bit to the center(so it won't go to the smaller ring) then set the cable, and set the lower limit back. But I do prefer to do the fine tune with the adjuting nuts. – dmb Feb 13 '18 at 20:45

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