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Curious indexing problem...

by PRSboy
Fri, Aug 27, 2021 09:57
7

My Ultegra 6800 rear derailleur is being a bit problematic at the moment; all gears work perfectly except the 11t where there is a lot of noise but it won't drop into the gear.  I've reindexed it a couple of times on a bike stand, and it works fine.  As soon as I ride it, it stops working!

All the various parts seem to be working fine individually, and it is a problem that seems to have started all by itself.  I replaced the inner cables and chain earlier this year, and fitted new carbon wheels.

Any thoughts on what else I should check?

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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7 comments

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PRSboy | 3 years ago
1 like

Ok, so turns out a half turn of the hi limit screw has indeed sorted it!  Feel a bit silly I didn't check it first, but anyhow, thanks for the suggestion.

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hawkinspeter replied to PRSboy | 3 years ago
0 likes

PRSboy wrote:

Ok, so turns out a half turn of the hi limit screw has indeed sorted it!  Feel a bit silly I didn't check it first, but anyhow, thanks for the suggestion.

Nice one and now you know more about adjusting gears too.

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Hirsute replied to PRSboy | 3 years ago
1 like

Great news. Still a bit odd that it didn't show up on the stand.

Edit
Don't forget to check it all in 4-6 weeks. Probably need to tweak the barrel adjuster.

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Hirsute | 3 years ago
1 like

Are your wheels 11 speed and shimano compatible ?

If you manually (or on the stand) put it into 11 and then try and ride it, does stay in 11 or drop to 10 ?

 

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hawkinspeter | 3 years ago
2 likes

I'd be looking at the limit screw and the B tension screw that affects how close the derailleur goes to the sprockets. However, it's strange that it can work well on the stand and not when you're putting some power through it. Maybe check that the cassette is tight with no movement.

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PRSboy replied to hawkinspeter | 3 years ago
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hawkinspeter wrote:

I'd be looking at the limit screw and the B tension screw that affects how close the derailleur goes to the sprockets. However, it's strange that it can work well on the stand and not when you're putting some power through it. Maybe check that the cassette is tight with no movement.

Thanks for the replies... I will check the torque on the lockring as I did it by feel rather than with my torque wrench.  I did fiddle with the H limit screw by bringing the mech inboard a little when I was setting the bike up with the new cables, so maybe I introduced an issue there.

I wish in retrospect that I'd changed the cable outers as its possible again the new inner has revealed a wear issue in the outer, but couldn't face it at the time (internal cable routing) when I was buying the parts.  As it happens I ended up taking them out by mistake and thankfully was far less difficult than I expected to refit them!

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AfterPeak | 3 years ago
1 like

Might be your limit screw? If you turn the H limit screw a quarter turn clockwise might resolve it.

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