Help with rear derailleur

Willam

Well-Known Member
Got a carrier bag stuck in my rear derailleur on my way home yesterday, it’s totally knocked my shifting out, not sure how? Chain doesn’t want to move from the smallest cog, I’ve tried following yt vids on how to adjust the RD, not sure if my model is different to the standard but can’t seem to find a vid that matches mine.

As far as I’ve got is I think I understand the high and low screw limits, I’ve loosened the cable and tried setting the high and low point but get lost after that?
The vids I’ve watched say to start with the chain on the small cog?
There doesn’t seem to be An adjustment screw on the cable, anyone any tips or can point me to a vid that may help.
 

cyberknight

As long as I breathe, I attack.
Some shifters have the adjustment screw where it enters the shift lever on flat bar bikes
 
OP
Willam

Willam

Well-Known Member
This clip about adjusting RDs might help you.....

View: https://www.youtube.com/watch?v=SkzvfCaIbyQ
wow I love this guy, he explains things just how I need to take in info! watched a few videos and he was by far the best, Thanks for the link!

Cyber knight I see I have an adjustment screw at the top, so feel with the video and now knowing where the screw is I should be able to fix the issue, thanks.
 

slowmotion

Quite dreadful
Location
lost somewhere
wow I love this guy, he explains things just how I need to take in info! watched a few videos and he was by far the best, Thanks for the link!

Cyber knight I see I have an adjustment screw at the top, so feel with the video and now knowing where the screw is I should be able to fix the issue, thanks.
Yes, he's pretty good. Lots of people on CC rate him very highly. Good luck with your RD.:okay:
 

gbb

Legendary Member
Location
Peterborough
Possible you've bent the hanger. They dont take much and a visual inspection from the rear, follow the chain line down from the cassette, it might be obvious. Equally, they can bend very slightly and not obviously, that will still impact your shifting.
Either way, if you struggle to get the RD adjust and work properly, suspect the hanger.
 

screenman

Legendary Member
Why on earth would the adjustment go out instantly when you got the bag caught, you have bent something and it needs straightening, you cannot do it by eye not even the most experienced mechanic can. Off to a decent shop or invest in an alignment tool.
 

Cycleops

Legendary Member
Location
Accra, Ghana
Yes, something is bent. Eyeballing it from the rear will show where the problem is. Safest to replace it if it’s the hanger but if it’s not too bad you can try to straighten it between the jaws of an adjustable wrench.
 

gbb

Legendary Member
Location
Peterborough
Yes, something is bent. Eyeballing it from the rear will show where the problem is. Safest to replace it if it’s the hanger but if it’s not too bad you can try to straighten it between the jaws of an adjustable wrench.
Been there, done that (tweaking it straight'ish with an adjustable)
Its not the perfect solution but it can get you going. My ebike RD was visibly out of line and shifting all over the place. Tweaked the hanger as best i could, shifting much improved but not perfect, but workable.
While this will in all probability NOT give you a perfect solution, it can get you goinge
 
OP
Willam

Willam

Well-Known Member
Posted late at night, this morning working through what I learnt last night and the fix, I was thinking how could a bag have messed with the shifting given the fix, at first I was thinking the high/low screws may have got knocked but that wouldn’t alter the shifting, and with the adjustment screw being on the handlebars that too couldn’t have been knocked so was coming back here to ask the question...but you all beat me to it, I’ll look into if it’s fixable ,if not I might as well buy a new RD as I’m guessing a bike shop repair would cost not much less.

looks like someone’s discarded 10p carrier cost me a few quid!

Cheers all.

edit oh crap, having now watched the above video, I was thinking it was the RD that might be bend, not the actual bike! yep think it’s off to a LBS! No spare wheel and I don’t trust myself with this, done most repair before BB, crankset etc but bending the bike frame is beyond my skill level. Scary a plastic bag can do that...scrap that £15 for a new one, I’m going for it! Got to love yt.
 
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rogerzilla

Legendary Member
Why on earth would the adjustment go out instantly when you got the bag caught, you have bent something and it needs straightening, you cannot do it by eye not even the most experienced mechanic can. Off to a decent shop or invest in an alignment tool.
You can do it with a long straight edge, some calipers and a good eye but the frame needs to be fairly well stripped first. The tool enables it to be done by just removing the rear mech.
 

screenman

Legendary Member
You can do it with a long straight edge, some calipers and a good eye but the frame needs to be fairly well stripped first. The tool enables it to be done by just removing the rear mech.
I prefer the easy way,the other requires some skill and if anyone doubts that then I suggest they try both ways. All I did in my first reply was to state the extremely obvious.
 
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