Rear Derailleur Shifts badly under tension

[Tim Hall]

I paid half of that and have never once tested a hanger that does not require tweaking.

Do all the bikes with out of whack hangers also have poor shifting, or can you get a badly aligned hanger and still shift OK? I'm guessing cassettes with fewer sprockets will be less susceptible to this.

 

[Milkfloat]

I would say about 4-5mm when measured at the rim is probably getting into the territory of really needing fixing. On my 5 speed and 8 speed bikes 'roughly straight' seems good enough.

 

[screenman]

Do all the bikes with out of whack hangers also have poor shifting, or can you get a badly aligned hanger and still shift OK? I'm guessing cassettes with fewer sprockets will be less susceptible to this.

Not poor shifting as I do not let them get that bad, but after a tweak you do feel better shifting and a quieter transmission.

 

[antnee]

Well Milk float I took your advice and removed the hanger put put it in the vice and used two mm rules (one as a straight edge and by measured over the distance of the top of the vice jaw found that the hanger was 2.5mm out of true so straighten it up and got the derailleur working really well from what it it was But still have a very slight rattling on all gears and on closer inspection saw that the top jockey wheel seems to move across on its bearing from one side to the other as bike is peddled in the work stand. Strange that? So I wondered if my other bike did anything similar, I saw that it was completely centred on its bearing so am at a loss now its back to the drawing board

 

[screenman]

Well Milk float I took your advice and removed the hanger put put it in the vice and used two mm rules (one as a straight edge and by measured over the distance of the top of the vice jaw found that the hanger was 2.5mm out of true so straighten it up and got the derailleur working really well from what it it was But still have a very slight rattling on all gears and on closer inspection saw that the top jockey wheel seems to move across on its bearing from one side to the other as bike is peddled in the work stand. Strange that? So I wondered if my other bike did anything similar, I saw that it was completely centred on its bearing so am at a loss now its back to the drawing board

That is not how it is done, many rear mechs are designed with bends in.

 

[winjim]

Well Milk float I took your advice and removed the hanger put put it in the vice and used two mm rules (one as a straight edge and by measured over the distance of the top of the vice jaw found that the hanger was 2.5mm out of true so straighten it up and got the derailleur working really well from what it it was But still have a very slight rattling on all gears and on closer inspection saw that the top jockey wheel seems to move across on its bearing from one side to the other as bike is peddled in the work stand. Strange that? So I wondered if my other bike did anything similar, I saw that it was completely centred on its bearing so am at a loss now its back to the drawing board

The hanger needs to be parallel to the cassette, not just straight with respect to itself. You really need to check it on the bike.

 

[screenman]

The hanger needs to be parallel to the cassette, not just straight with respect to itself. You really need to check it on the bike.

I fear despite trying to help we maybe wasting our time.

 

[antnee]

No your not. Have read all the posts and realise what your saying plus watched all the you Tube videos on the subject I just don't want to have to spend out more money than I need at the moment, though have seen one you-tube clip where a bloke makes one himself which works just fine for him so I fancy having a go at that after have spent some considerable years in one form of service engineering can't see too many problems, so all of you were not wasting good finger power in advising me. Thanks all

 

[screenman]

No your not have read all the posts and realise what your saying plus watched all the you Tube vidios on the subject I just don't want to have to spend out more money than I need at the moment, though have seen one you-tube clip where a bloke makes one himself which works just fine for him so I fancy having a go at that after have spent some considerable years in one form of service engineering can't see too many problems ,so you were not wasting good finger power in advising me Thanks all

Thank you for the assurance, the rear mech will certainly be out of alignment.

 

[raleighnut]

Well Milk float I took your advice and removed the hanger put put it in the vice and used two mm rules (one as a straight edge and by measured over the distance of the top of the vice jaw found that the hanger was 2.5mm out of true so straighten it up and got the derailleur working really well from what it it was But still have a very slight rattling on all gears and on closer inspection saw that the top jockey wheel seems to move across on its bearing from one side to the other as bike is peddled in the work stand. Strange that? So I wondered if my other bike did anything similar, I saw that it was completely centred on its bearing so am at a loss now its back to the drawing board

When you spin the rear wheel does the cassette 'oscillate' slightly, I've had freewheels that do but not seen it on a 'freehub'

 

[southcoast]

As I have successfully adjusted quite a few sets of new cables to rear derailleurs I am surprised to find that am having a few problem with this, because after fitting new cassette,chain and longer cage rear derailleur find that whole gear changing operation works perfectly when bikes on the work stand though as soon as any real pressure is put on the pedals more often than not chain either does not shift straight away or jumps two sprockets! I can only put this down to my inability to adjust the rear cable tension properly and can't think it could be anything else as the old setup with shorter cage derailleur worked quite well
I would be interested to hear anybody's thoughts on this
P.s Have tried adjusting during test rides but so far have have limited success. Many thanks

To change gear it is best not to do it under load. Just pedal gently with no pressure on pedals.