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I have a Shimano Tiagra 4700 10 speed group set.

I can only get 9 gears working - the shifting is smooth with no jumps but one gear is missing, either at the top or bottom depending how I setup the rear mech. If I disconnect the cable from the rear mech and then hold the cable by hand I can feel the shifters click through 8 times - one click too few!!. So the problem seems to be in the shifter, as if there is something blocking the shifter from turning that last slot.

Could it be a faulty shifter? Is it easy to take them apart to check?

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  • FYI I removed the link to Chain Reaction as it was broken and did not point to the product page (for me at least) I added in the 4700 series name as that identifies the group set – Argenti Apparatus Feb 3 '19 at 15:53
  • Also, in the last sentence I think you mean the shifter is faulty not the mech. – Argenti Apparatus Feb 3 '19 at 15:54
  • I've just discovered the same after tweaking everything - I've just realised the same thing (mine came from Ribble - early 08). I could never get it right - it's not me it's the wrong part - Bobbins – David Lapeš Jun 30 '20 at 22:26
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By removing the cable from the derailleur and operating the shifter while applying tension to the cable by hand you have proved the shifter is the problem (unless the cable is hanging up somewhere, it's best to do this test holding the cable as close to the shifter as possible).

Sometimes shifters can get a bit of dried grease or dirt in them that prevents a pawl from catching on a ratchet. Unfortunately they cannot be disassembled as they are riveted together.

Soaking with WD40 or equivalent and/or blowing out with a compressed air hose can reportedly clear the contamination.

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  • Thanks - grease or dirt seems a plausible explanation. It is about 2 years old, but unused, so too late to return for a refund. Perhaps grease has dried whilst it was lying around. With a bit of luck it might clear with some use. If not I'll remove from handlebars and try clearing with compressed air. – stuartc Feb 3 '19 at 17:10

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