Install question on R8000 rear install question on the Ultegra R8000 rear derailleur
09-27-20, 11:11 PM
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Install question on R8000 rear derailleur
Today, I replaced my R8000 SS rear derailleur with a longer-cage version of the same unit. Before attaching the cable, I noticed that the jockey wheels would not swing out to the smallest cog. I opened (unscrewed) the Top Adjustment Screw almost to the point of falling out, and the cage still wouldn't move. When I later mounted the cable and the chain, the RD wouldn't shift to anything smaller than the 3rd of 4th smallest cogs.
What might be causing this to happen?
What might be causing this to happen?
Last edited by Robert A; 09-27-20 at 11:29 PM.
09-28-20, 04:01 AM
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Sounds weird. I'd say you're best placed to figure that out, unless you post a bunch of good pics from all different angles...
09-28-20, 04:24 AM
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Done this before and the cable was too tight. Did you remove the cable and manually see if it will travel out to the smallest cog?
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09-28-20, 04:44 AM
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Today, I replaced my R8000 SS rear derailleur with a longer-cage version of the same unit. Before attaching the cable, I noticed that the jockey wheels would not swing out to the smallest cog. I opened (unscrewed) the Top Adjustment Screw almost to the point of falling out, and the cage still wouldn't move. When I later mounted the cable and the chain, the RD wouldn't shift to anything smaller than the 3rd of 4th smallest cogs.
Some basic starting points...turn both limits screw out (counter-clockwise), and then manually move the derailleur body to the allowed limits without the cable attached. Adjust the screws accordingly so the top jockey wheel lines up just past the inner/outer cog...less than 1mm past "dead center." Also, remember, the natural resting position of a mechanical derailleur is under the small cog, if it is not going there, it is being physically blocked from doing so. Have you checked to ensure that there is nothing fouling the derailleur pivots?
If you cannot get the derailleur to move to line up on either end of the cassette, is your derailleur hanger straight, or loose? Also, and I assume you did, is the fixing bolt on the derailleur fully installed to the derailleur hanger?
09-28-20, 09:15 AM
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Is the tab that is supposed to bear against the notch on the derailleur hanger hitting the side of the hanger? And this should be posted in 'mechanics' not GD.
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09-28-20, 10:19 AM
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09-29-20, 08:14 PM
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If the RD isn't screwed in all the way, it won't reach the biggest cogs, not the smallest...
