Derailleur Query

[MudLark]

Hi guys,

I have a bit of an odd issue I'm trying to figure out with a Dura Ace RD. I have it on an older Spez Diverge with a 2x11 setup and a Rapide derailleur hanger extender.

I'm not the world's most experienced bike mechanic but I have set up a lot Shimano RD's without issues. 

Anyway, setting up this RD correctly on a bike stand, everything works as it should on the stand. But when on the smallest sprocket (and this only happens on the smallest sprocket) and only when under power/load, the chain will intermittently try to climb up to number 10 sprocket and then immediately drop off; it seems to only just catch every now and then -msay every 10 or 20 pedal strokes. For some reason I just can't seem to get it quite right. 

Leaving aside the usual advice about fine tuning the derailleur adjustment, is there something else relatively common or known to happen that I might be overlooking?

TIA!

 

[Andreas_187]

Are you sure the hanger is straight?

Edited May 28, 2023 by Andreas_187

[RobertWhitehead]

1) Is the quick link on the chain fully engaged? 

2) How old is the gear cable, I have found that sometimes even with brand new cables I just can't seem to get it 100% on literally one gear going up or down. The moment I swop the cable it sorts the problem 

[MudLark]

1 hour ago, Andreas_187 said:

Are you sure the hanger is straight?

Good point. I think so but will check it again.

[MudLark]

30 minutes ago, RobertWhitehead said:

1) Is the quick link on the chain fully engaged? 

2) How old is the gear cable, I have found that sometimes even with brand new cables I just can't seem to get it 100% on literally one gear going up or down. The moment I swop the cable it sorts the problem 

1. Yes but will check it also again. 

2. I have no idea. Used bike I bought about a year back. I wonder if this could be it. Cheap enough to change.

[Thomo]

I had a gearing issue once ... turned out to be the cassette spacer on that specific wheelset.

[Martin PJ]

Quick link is directional. Check it is correct. I have had problems like this. Happens on the 11 t.

[Marcv]

So my experience is with a mtb, but when i have had this issue its because I've put a new chain on a worn cassette. if that is the case i don't think there is a solve except to put the old chain back and ride it till it breaks....or get a new cassette.

Hope this helps

[MudLark]

11 hours ago, Martin PJ said:

Quick link is directional. Check it is correct. I have had problems like this. Happens on the 11 t.

Good one.

[MudLark]

10 hours ago, Marcv said:

So my experience is with a mtb, but when i have had this issue its because I've put a new chain on a worn cassette. if that is the case i don't think there is a solve except to put the old chain back and ride it till it breaks....or get a new cassette.

Hope this helps

Both casette and chain are new in this case. But thank you.

[Martin PJ]

26 minutes ago, MudLark said:

Good one.

Funny story, just checked my mtb now and the link is facing wrong. I rode an mtb race yesterday, my chain was slipping in 11t.

[MudLark]

Just checked. Bike has a KMC chain and quick link. KMC say their links are not directional. Tried flpping it over anyway. I have some other new quick links. Will try one because thinking about it, the frequency with which the 'skip' occurs indicates that it could well be the quick link only just catching.

[Mongoose!]

.

Edited May 29, 2023 by Mongoose!

[Martin PJ]

1 hour ago, MudLark said:

Just checked. Bike has a KMC chain and quick link. KMC say their links are not directional. Tried flpping it over anyway. I have some other new quick links. Will try one because thinking about it, the frequency with which the 'skip' occurs indicates that it could well be the quick link only just catching.

I tested mine now more closely, the link is not the problem. I think it is the limit screw needs a bit of adjustment. If that doesn't work, then the 11t cog must be worn. I cannot see any bent teeth, but this isn't always obvious as the teeth are different shapes to assist with chain movement on gear changes.

[Jewbacca]

I'd just adjust the limit screw slightly and see if that works.

The chain is at a helluva angle on the smallest cog and sometimes it might catch the ramps if it's jiggling.

 

[dasilvarsa]

Hanger Extenders will cause the 11T and 12T to Wear Prematurely on some Systems.