Rear derailleur is rubbing cassette

[alewater]

Hi all, thanks for the info so far.

Please see the additional photos.

@Ajax Bay The rear cassette has 7 gears, can you tell me how to measure it and to figure out the range? I can't see any model number anywhere. The rear shifter has 7 positions and 7 clicks. The only text on the cable pulley wheel is "Directional Pulley".

@figbat Thanks for the highlights, I thought that was the B screw as well but it literally does nothing, you can see in the photos that it doesn't press against anything. When I screw it there is no resistance and nothing touches the end regardless of the gear. Makes me think the derailleur has been knocked (evidence of the bent cage) and might be missing a small piece (B screw not pressing on anything).

The only text I can find that refers to a model number is on the cassette which is MF-TZ07

 

[Ajax Bay]

The rear freewheel has 7 sprockets (cogs)

FTFY
https://www.rmcbikes.com/en/shimano-mf-tz21.html
Largest sprocket is therefore 28 so within RD's spec (see datasheet ^^ shared by @figbat ).
The bent cage outer plate is steel. Two screws hold it on (and are the axles for the jockey wheels). Worth removing, straightening the plate and reassembling.
B screw adjustment is the normal way of adjusting the angle of the mech body to drop the top (guide) jockey wheel down, away from the sprockets, to ensure an 'air gap'.

 

[figbat]

Your derailleur model number is here:

Using this info I posted a link to the instruction manual that covers this model upthread.

 

[alewater]

Your derailleur model number is here:

View attachment 525610

Using this info I posted a link to the instruction manual that covers this model upthread.

Now that’s what I call eagle eyes!!!

RD-TX50

 

[wajc]

Adjusting screws mentioned by 3 contributors, OP included. My point is folk should carefully consider what's wrong before making adjustments or you could make things worse. 40 years of cycling I only ever had to adjust a RD once, when I fitted a new one. All things being even, they don't generally move on their own IME. Just an observation.

I'd say this is a good point - the bike apparently was OK and then 3 years later it isn't. After being taken out from wherever it had been stored we are shown pics of the rear mech which look like it is damaged.

Makes you wonder if the rear mech had been struck by something whilst in storage or judging by the bend of the outer cage hooked up on something and then pulled outwards. That might explain the separation that @figbat clearly points out (there appear to be a couple of marks on the inside as well that might back this up).

I'd carefully bend the outer plate back to where it should be if possible and then check and adjust mech alignment before doing anything else.

 

[Ajax Bay]

The rear shifter has 7 positions and 6 clicks

FTFY

 

[alewater]

I'd say this is a good point - the bike apparently was OK and then 3 years later it isn't. After being taken out from wherever it had been stored we are shown pics of the rear mech which look like it is damaged.

Makes you wonder if the rear mech had been struck by something whilst in storage or judging by the bend of the outer cage hooked up on something and then pulled outwards. That might explain the separation that @figbat clearly points out (there appear to be a couple of marks on the inside as well that might back this up).

This makes sense, I don’t remember anything happening to it but the wife’s bike is always parked next to it.

Regarding the B screw - As you can see in the pictures when it’s screwed in it’s not touching anything, is it missing something?

Thanks again

 

[wajc]

This makes sense, I don’t remember anything happening to it but the wife’s bike is always parked next to it.

Regarding the B screw - As you can see in the pictures when it’s screwed in it’s not touching anything, is it missing something?

Thanks again

This is a good video on the B screw adjustment and the effect it has. Check to see if you are able to see any movement in the derailleur position as described.

B Screw Adjustment

The B screw should move against something, see the pic in this link - note yours is not the same and this person is having issues where his B screw is not hitting the mech hanger but it will give you an idea of how it just pushes up against something.

B screw pic

If you can't see any movement at all I'd wonder whether the damage is not limited to the bent cage already mentioned.