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My RD-4700 rear derailleur is having some trouble shifting into the highest gears / smallest cogs.

When I shift up past about 6th or 7th the shifter paddles just go floppy.

I've taken the chain off and it looks like the RD doesn't want to go up to 10th at all. I can pull the derailleur over up to 10th but it doesn't want to go there on it's own.

Lower gears seem OK. Definitely ridable.

 

Probably relevant: Shortly before the issue began I threw a chain and put it back on after taking one damaged link off.

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  • Did you touch the inner cable at all? Are there any other damaged links in the chain?
    – Criggie
    Aug 22, 2022 at 20:32
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    @Criggie No other damaged links. I re-set the tension on the inner cable using the shifter's barrel adjuster during the last ride, and just now have re-tensioned at the pinch bolt. It feels like a lack of tension on the inner cable in the higher gears. Even with no chain installed the RD doesn't go up to the highest gear.
    – Scottmeup
    Aug 22, 2022 at 20:44

3 Answers 3

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Your cable is probably starting to wear somewhere, usually close to the shifter. Because cables are multi-stranded, when some strands break they prevent the cable from entering back into the cable housing when you release the cable tension. Floppy shifter paddles before you reach the smallest cogs is a typical symptom of this.

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  • That’s probably the reason. Even good cables tend to fray and break inside the Brifters after a few thousand kilometers.
    – Michael
    Aug 23, 2022 at 7:42
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If you detach your shifter cable it should default into the smallest cog. If it's not going into the smallest cog with the cable detached then check your limit screw.

Generally when I'm adjusting my derailleur, I'll follow this procedure

  1. Detach Cable
  2. Adjust limit screw so it runs properly on smallest cog.
  3. Put barrel adjuster almost all the way in, with a small amount of room to loosen it.
  4. Re-attach cable making sure it's reasonable tight, but not so tight that it will shift info second smallest cog, making sure cable outers are properly seated in all cable stops.
  5. Shift into second smallest cog and if it doesn't make it then use barrel adjuster until it has enough tension to get into second smallest gear.
  6. Shift back into smallest gear to make sure it goes there, using barrel adjuster if necessary.
  7. Go through all gears on cassette and do fine adjustments with barrel adjuster to make sure all the gears are working properly.
  8. Check the limit screw for the biggest cog to make sure you can't shift into the wheel. You should try pushing with your hand as indexed shifters often won't shift past the last cog. You can do a visual inspection on the limit screws to ensure they are touching against the stop when the derailleur is in the biggest and smallest cogs.

A nice tip I learned for dealing with the barrel adjuster is to turn it in the direction you want the chain to go. For instance, if the chain doesn't go to the bigger cog when it is supposed to, turn the barrel adjuster towards the wheel. If it's not going down to a smaller cog, then turn it away from the wheel until it makes the necessary shift.

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Echoing Sylvain's answer (I wanted to just comment, but can't due to insufficient reputation points). I just went through this with my Sora shifter. Mine broke with roughly 25 mm of completely frayed wires still attached to the metal cylinder (the cable end that goes in the brifter). I had approximately 7000 km on the bike at the time of failure.

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