Derailleur stretching out

General cycling advice ( NOT technical ! )
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Northeastperson
Posts: 31
Joined: 15 Nov 2021, 2:59pm

Derailleur stretching out

Post by Northeastperson »



Hi. The last time I went out on the bike it was functioning ok but just turning the pedals (on my new bike stand :oops: ) without changing gear it's doing this.





I'm guessing I'm the culprit. All I've done is degrease the chain and relube it trying to do exactly what GCN show in one of their videos. I haven't adjusted anything. :(
Last edited by Northeastperson on 27 Nov 2021, 2:55pm, edited 5 times in total.
richardfm
Posts: 969
Joined: 15 Apr 2018, 3:17pm
Location: Cardiff, Wales

Re: Derailleur stretching out

Post by richardfm »

What's happening at the chain ring when it does that?
Richard M
Cardiff
Northeastperson
Posts: 31
Joined: 15 Nov 2021, 2:59pm

Re: Derailleur stretching out

Post by Northeastperson »

richardfm wrote: 27 Nov 2021, 11:30am What's happening at the chain ring when it does that?
Ok I might have worked that out. The lever for the rear derailleur must have been between clicks or something. I clicked it again and the derailleur stopped stretching out.

I feel the site should have another section for total beginner bike maintenance numpties. I feel I'm stinking out this part of the forum. :)
Northeastperson
Posts: 31
Joined: 15 Nov 2021, 2:59pm

Re: Derailleur stretching out

Post by Northeastperson »

I managed to upload my YouTube video but only the link. How do you get the image of the video appearing in a post? Clicking on the YouTube button on the edit post option didn't do it.
Jdsk
Posts: 24639
Joined: 5 Mar 2019, 5:42pm

Re: Derailleur stretching out

Post by Jdsk »

Northeastperson wrote: 27 Nov 2021, 12:07pm How do you get the image of the video appearing in a post? Clicking on the YouTube button on the edit post option didn't do it.
You only put the unique identifier of the YouTube piece between the YouTube markers, not the entire URL. In this case that's 6p5gcBn6s5Y rather than https://www.youtube.com/watch?v=6p5gcBn6s5Y.

Jonathan

Jdsk
Posts: 24639
Joined: 5 Mar 2019, 5:42pm

Re: Derailleur stretching out

Post by Jdsk »

Northeastperson wrote: 27 Nov 2021, 12:03pmI feel the site should have another section for total beginner bike maintenance numpties. I feel I'm stinking out this part of the forum.
Don't feel like that. : - )

I recommend

Sheldon Brown:
https://www.sheldonbrown.com

Park Tool Repair Help:
https://www.parktool.com/blog/repair-help

Jonathan
Northeastperson
Posts: 31
Joined: 15 Nov 2021, 2:59pm

Re: Derailleur stretching out

Post by Northeastperson »

Jdsk wrote: 27 Nov 2021, 12:37pm
Northeastperson wrote: 27 Nov 2021, 12:03pmI feel the site should have another section for total beginner bike maintenance numpties. I feel I'm stinking out this part of the forum.
Don't feel like that. : - )

I recommend

Sheldon Brown:
https://www.sheldonbrown.com

Park Tool Repair Help:
https://www.parktool.com/blog/repair-help

Jonathan
Thanks for the advice Jonathan.
nirakaro
Posts: 1578
Joined: 22 Dec 2007, 2:01am

Re: Derailleur stretching out

Post by nirakaro »

Northeastperson wrote: 27 Nov 2021, 12:03pm I feel the site should have another section for total beginner bike maintenance numpties. I feel I'm stinking out this part of the forum. :)
Hey we were all total beginners once. And no-one makes us read your posts - if we read them it's because we're interested and willing to help.
LollyKat
Posts: 3250
Joined: 28 May 2011, 11:25pm
Location: Scotland

Re: Derailleur stretching out

Post by LollyKat »

+ 1
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[XAP]Bob
Posts: 19793
Joined: 26 Sep 2008, 4:12pm

Re: Derailleur stretching out

Post by [XAP]Bob »

Northeastperson wrote: 27 Nov 2021, 12:03pm I feel the site should have another section for total beginner bike maintenance numpties. I feel I'm stinking out this part of the forum. :)

Even old hands need beginners to remind them of the basics...
Hopefully I've fixed a lift by virtue of giving it power :lol:
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
gregoryoftours
Posts: 2234
Joined: 22 May 2011, 7:14pm

Re: Derailleur stretching out

Post by gregoryoftours »

Northeastperson wrote: 27 Nov 2021, 12:03pm
richardfm wrote: 27 Nov 2021, 11:30am What's happening at the chain ring when it does that?
Ok I might have worked that out. The lever for the rear derailleur must have been between clicks or something. I clicked it again and the derailleur stopped stretching out.

I feel the site should have another section for total beginner bike maintenance numpties. I feel I'm stinking out this part of the forum. :)
The video shows that your rear derailleur is jumping between 2 rear gears (the chain is catching and lifting up onto the next biggest sprocket which also causes the derailleur arm to swing forward, but then dropping back down again). This is a gear tuning issue. If the problem recurs it could have one or more of many causes, incorrect cable tension/derailleur or hanger alignment is out/excessive cable friction etc etc. Sometimes gears can behave better or worse in the stand than when actually riding as different forces are exerted. If it works ok when riding then don't worry.
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