Rear mech

[Andywinds]

Hi all.
2 months ago my rear mech hanger broke and so it has taken me a while to get a replacement. I am not sure but I think my mech is bent. When I shift up the largest cog part of the mech if hitting the spokes. When the hanger broke the mech did hit the spoke a little, but I was riding up hill at about 4 mph. Is it worth just buying a replacement?

 

[Arjimlad]

It is quite possible the mech is bent - does it hang straight off the mech hanger when looked at from the rear ?

It is also possible that the area which the mech hanger clamps to, has itself got out of alignment and may need re-setting. I had a mudguard get sucked up into my rear wheel after the mount snapped on a fast bit of rough road, resulting in the mech getting dragged into the rear wheel & snapping at the hanger.

 

[Andywinds]

Pic of rear mech.

 

[Andywinds]

It is quite possible the mech is bent - does it hang straight off the mech hanger when looked at from the rear ?

It is also possible that the area which the mech hanger clamps to, has itself got out of alignment and may need re-setting. I had a mudguard get sucked up into my rear wheel after the mount snapped on a fast bit of rough road, resulting in the mech getting dragged into the rear wheel & snapping at the hanger.

The rear hanger just broke off while riding up hill, it was not from an impact. But there were signs of a knock on the rear mech when I got the bike. But never had any issues with this before. Hopefully you can see the mech above. Yes it does look out of shape.

 

[Andywinds]

Rear mech

 

[Andywinds]

Here is a pic showing rear hanger.

 

[raleighnut]

When you fit a new gear hanger the alignment needs to be set using a proper tool.

 

[Andywinds]

When you fit a new gear hanger the alignment needs to be set using a proper tool.

So you cannot just fit a new hanger and then mech? Is the hanger not already set to my frame? Does my rear mech look ok from the pic

 

[Tojo]

I think the rear mech looks out of alignment on your first pic the top jockey wheel doesn't seem to be in line with the corresponding cog on the cassette, it is probably wise to get the alignment of the hanger checked and go from there.

 

[Andywinds]

I think the rear mech looks out of alignment on your first pic the top jockey wheel doesn't seem to be in line with the corresponding cog on the cassette, it is probably wise to get the alignment of the hanger checked and go from there.

So do we think that the rear dropouts are bent. The hanger is new so that is fine. It is normal to have to align a new hanger? Is it worth picking up a new rear mech as well?

 

[raleighnut]

So you cannot just fit a new hanger and then mech? Is the hanger not already set to my frame? Does my rear mech look ok from the pic

The hanger needs to be set to your individual frame, with some frames it might be in-line and another hanger may be better aligned on your frame but they need to be tweaked to align perfectly. It's a 2 minute job.

 

[Andywinds]

The two jockey wheels look out if alignment as well.

 

[Andywinds]

The hanger needs to be set to your individual frame, with some frames it might be in-line and another hanger may be better aligned on your frame but they need to be tweaked to align perfectly. It's a 2 minute job.

Right ok thanks. would you advise that I pick up a hanger tool? I would go to wiggle but they are out of stock.

 

[raleighnut]

Right ok thanks. would you advise that I pick up a hanger tool? I would go to wiggle but they are out of stock.

I get a local shop to do mine, couple of quid in the 'tea fund' sorts them out but all bar 1 of my bikes are steel so the hanger is integral to the frame

 

[Andywinds]

I get a local shop to do mine, couple of quid in the 'tea fund' sorts them out but all bar 1 of my bikes are steel so the hanger is integral to the frame

The issue I have is one of the shops near me has got things wrong before that is why I was wanting to be more self sufficient. Are rear mech generally pretty tough?