Strange real derailleur behaviour

[Cyclenon]

Hi,

The chain on my rear derailleur (105) is jumping around when shifting down from the biggest cog to the 4th/5th (i.e. from lowest to highest gear).

Shifting the through the first three cogs is absolutely fine, nice and smooth with no jumping.
However, once I shift into the 4th / 5th the issues start.

I have removed the cable, reset high / low limits as needed but the issue remains.

What's puzzling me is that if there was a problem with indexing then would it not affect all gears the same, rather than those starting from 4th / 5th onwards?

Thanks

 

[the snail]

Sounds like the cable is not moving smoothly or maybe the derailleur needs cleaning/lubing?

 

[Cyclenon]

I thought it was pretty clean / lubed. Cables are new.
I'll give it another clean and let you know.

Thanks

 

[screenman]

Rear mech hanger alignment, is often the cause of this problem.

 

[Nigelnaturist]

Are these the gears you use most, and how old is the cassette, because if you ride on these gears the most they will be more worn than the others and likely to skip/jump.
Just a thought, as I ride mainly on the 17/16 tooth range.

 

[Cyclenon]

Forgot to add that bike is brand new (although has been in storage or the last year).
I suspect mech alignment too...

 

[fossyant]

Ah, change the cables..... New, in storage...?

Had real crap braking from my daughter's cable disc braked bike, brand new. I changed the cables... Works fine.. Storage and moisture.

 

[Nigelnaturist]

Clean the cables and make sure you clean the cable guide at the bottom of the BB, you should not need to adjust the hi and low stops once they are set, make sure there are no kinks on the inner cables especially through the outers.

 

[TheJDog]

My bike was doing this, and the mech hanger was a bit loose. Tightened it up, no more derailleur problem (at the rear, anyway )

 

[Cyclenon]

Turns out it was a bent mech hanger... Thanks for your help