Rear mech alignment issue

[Monsieur Remings]

Okay, will try and get some photos tomorrow but very difficult I'd imagine to see on a photo.

I noticed after a ride that my Cube Acid 2013 was skipping gears and realised there was a slack cable. Upon further inspection, the gears weren't shifting at all properly. I thought I'd take it to LBS to replace cable if I couldn't get it taught again but I did, and got on with cleaning the bike thinking I'd have a go at adjusting it all properly a bit later. I took the chain off during the clean up as well and afterwards found that I couldn't replace the chain at all, it kept slipping off the jockey wheel and that the rear mech was not at all aligned with the cassette?

The wheel is in position properly, the cassette is on properly and when you look at the mech it looks straight enough, but something is not right and I can only figure it is the mech hanger..? I guess the derailleurs being long cage, any slight bend is exacerbated, right? I've tried the H and L screws but the angle is all wrong and I'm at a loss to understand what the hell's going on?

Any ideas out of the hat as to what the problem could be and how I can put it right..? I know, piece of string in my pocket etc.

Thanks for any input.

 

[RecordAceFromNew]

A piece of string indeed...

A couple of observations. Bending a hanger by itself would not make a rear mech's cable go slack. The best way to see what is going on is probably to put the bike on a stand as vertically as you can and observe from behind, to see how vertical / parallel the mech is to the rear wheel, and to see the alignment of the top jockey wheel with the rear sprockets.

Assuming you do not have a rapid rise / low normal rear mech then the H limit screw should position the top jockey to exactly below the smallest sprocket when the cable is completely slack, and once the cable is tensioned each click of the shifter should move it exactly one sprocket up etc. and the L limit screw should stop the mech from going beyond the largest.

But of course like a piece of string there can be many other reasons/causes to your problem.