Chain "jumps" and want to shift to a bigger cog.
05-02-23, 04:49 AM
#1
Newbie
Thread Starter
Chain "jumps" and want to shift to a bigger cog.
Hi
I'm having trouble with my rear derailleur, it wants to shift down to a bigger cog all the time, it doesn't do it but it wants to, making the chain jump.
I've tried putting more/less tension on the cable, tried adjusting the derailleur but it doesn't seem to make a difference.
I use a down tube friction shifter and a single chain ring in front(Wich is slightly oval, might be the problem, but it shouldn't be based on... what I've read on the internet
).
I recorded a clip of how it looks. https://youtu.be/KZbtNYWVtr4
Any help welcome!
I'm having trouble with my rear derailleur, it wants to shift down to a bigger cog all the time, it doesn't do it but it wants to, making the chain jump.
I've tried putting more/less tension on the cable, tried adjusting the derailleur but it doesn't seem to make a difference.
I use a down tube friction shifter and a single chain ring in front(Wich is slightly oval, might be the problem, but it shouldn't be based on... what I've read on the internet
).I recorded a clip of how it looks. https://youtu.be/KZbtNYWVtr4
Any help welcome!
05-02-23, 05:14 AM
#2
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Locate the place in the chain where it skips and see if you have a twisted link. What is the condition of your drivetrain? What is new, what is old?
05-02-23, 05:29 AM
#3
Industry guy
Has the bicycle fallen over and the derailleur hanger is now bent?
A visual inspection fro mthe rear of the bicycle will shed some light on this possible explaination.
rusty
A visual inspection fro mthe rear of the bicycle will shed some light on this possible explaination.
rusty
05-02-23, 06:59 AM
#5
Newbie
Thread Starter
Yes! And when putting pressure on it, it will change to a bigger cog from time to time.
05-02-23, 07:37 AM
#6
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This is a first! I've never seen anyone run through the gear turning the cranks backwards.
But I'm going to assume you also have this issue while on the bike and pedaling forward. So a bent DR hangar will be the first suspicion. But before going to the trouble of taking it to a bike shop to let them check for certain, I'd also just make sure the cable isn't just binding up and slow to pay out completely as you shift. But that would mean you'd only experience the jumping chain as you shifted the rear to the smaller high ratio cogs.
You might just hang that top tube over the corner of a table that has a lot of overhang and then turn the cranks the proper direction. Make a video of that and post again and let us know if that changes anything you perceive. As well, just let us know if it happens when shifting to the larger low ratio cogs or to the smaller high ration cogs or both ways.
When you pedal backwards and attempt to shift, it's not at all the same things going on. With the chain being pulled from below, the DR cage will be pulled on and not quite in the alignment it should be or will be when pedaling forward. So all bets are off whether it even can be adjusted correctly.
Welcome to BF!
But I'm going to assume you also have this issue while on the bike and pedaling forward. So a bent DR hangar will be the first suspicion. But before going to the trouble of taking it to a bike shop to let them check for certain, I'd also just make sure the cable isn't just binding up and slow to pay out completely as you shift. But that would mean you'd only experience the jumping chain as you shifted the rear to the smaller high ratio cogs.
You might just hang that top tube over the corner of a table that has a lot of overhang and then turn the cranks the proper direction. Make a video of that and post again and let us know if that changes anything you perceive. As well, just let us know if it happens when shifting to the larger low ratio cogs or to the smaller high ration cogs or both ways.
When you pedal backwards and attempt to shift, it's not at all the same things going on. With the chain being pulled from below, the DR cage will be pulled on and not quite in the alignment it should be or will be when pedaling forward. So all bets are off whether it even can be adjusted correctly.
Welcome to BF!
Last edited by Iride01; 05-02-23 at 07:42 AM.
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05-02-23, 07:54 AM
#7
Newbie
Thread Starter
This is a first! I've never seen anyone run through the gear turning the cranks backwards.
https://youtu.be/KZbtNYWVtr4
But I'm going to assume you also have this issue while on the bike and pedaling forward. So a bent DR hangar will be the first suspicion. But before going to the trouble of taking it to a bike shop to let them check for certain, I'd also just make sure the cable isn't just binding up and slow to pay out completely as you shift. But that would mean you'd only experience the jumping chain as you shifted the rear to the smaller high ratio cogs.
You might just hang that top tube over the corner of a table that has a lot of overhang and then turn the cranks the proper direction. Make a video of that and post again and let us know if that changes anything you perceive. As well, just let us know if it happens when shifting to the larger low ratio cogs or to the smaller high ration cogs or both ways.
When you pedal backwards and attempt to shift, it's not at all the same things going on. With the chain being pulled from below, the DR cage will be pulled on and not quite in the alignment it should be or will be when pedaling forward. So all bets are off whether it even can be adjusted correctly.
Welcome to BF!
https://youtu.be/KZbtNYWVtr4
But I'm going to assume you also have this issue while on the bike and pedaling forward. So a bent DR hangar will be the first suspicion. But before going to the trouble of taking it to a bike shop to let them check for certain, I'd also just make sure the cable isn't just binding up and slow to pay out completely as you shift. But that would mean you'd only experience the jumping chain as you shifted the rear to the smaller high ratio cogs.
You might just hang that top tube over the corner of a table that has a lot of overhang and then turn the cranks the proper direction. Make a video of that and post again and let us know if that changes anything you perceive. As well, just let us know if it happens when shifting to the larger low ratio cogs or to the smaller high ration cogs or both ways.
When you pedal backwards and attempt to shift, it's not at all the same things going on. With the chain being pulled from below, the DR cage will be pulled on and not quite in the alignment it should be or will be when pedaling forward. So all bets are off whether it even can be adjusted correctly.
Welcome to BF!
I'll do what you suggested later tonight!
Thanks for the response and the welcome!
05-02-23, 08:06 AM
#8
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I would agree with everything already mentioned and also noticed there appears to be a stiff link as you can see it as it goes through the pulleys.
05-02-23, 09:02 PM
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When you pedal forward, the chain passes through the rear derailleur cage so it lands on the selected cog. The derailleur "tells" the chain where to go. When you pedal backwards, the chain ring tells the chain where to go. The chain tries to follow a direct line from the chain ring to the cluster. So if the chain position on the cluster doesn't agree with position the derailleur, the chain jumps. It is utterly pointless to diagnose a drivetrain problem on a derailleur-equipped bike by pedaling backwards.
05-02-23, 11:03 PM
#10
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the chain has a bad link or two.... tight and /or twisted links.. it's fairly obvious.
hard to say if the der. hanger is bent.. it might have a slight bend to the outside, but not much....
hard to say if the der. hanger is bent.. it might have a slight bend to the outside, but not much....
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05-03-23, 06:56 AM
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I had the same issue with my bike. When i took it to the bike shop the mechanic told me after a while the chain gets stretched. You might want to consider getting new chain
