Problems with rear derailleur again !

Russ34

Pedelecer
Oct 11, 2021
58
11
54
Teignmouth
Hi, I’ve replaced the chain and rear cassette on my bike , all was good until I did 30 miles today and the chain started to jump again , I’ve spent hours trying to set it up but it just doesn’t want to play ! Does anyone have any suggestions please ? Is it possible that some at ups aren’t suitable for an ebike conversion? Many thanks
 

guerney

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Sep 7, 2021
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Have you tried adjusting the chain tension, via the screw on the derailleur? My chain jumped about infuriatingly (bbs01b) until I removed three links and adjusted chain tension. But mine is an odd Dahon folding bike, and I had no idea how many links my chain was supposed to have in the first place.
 
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Russ34

Pedelecer
Oct 11, 2021
58
11
54
Teignmouth
Have you tried adjusting the chain tension, via the screw on the derailleur? My chain jumped about infuriatingly (bbs01b) until I removed three links and adjusted chain tension. But mine is an odd Dahon folding bike, and I had no idea how many links my chain was supposed to have in the first place.
Yeah the chain is the tightest it can be , I’ve had to lose more links as the chain snapped whilst trying it earlier
 

guerney

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Sep 7, 2021
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Yeah the chain is the tightest it can be , I’ve had to lose more links as the chain snapped whilst trying it earlier
Is it jumping like it wants to move to the next cog up? Or is it jumping off the smallest cog onto the axle? Maybe adjust the two adjustment screws on the derailleur? Or is it jumping in place on that smallest gear cog? Make sure zipties are not squeezing any of the gear cable sheaths. I replaced all of my gear cable sheaths, because they were sticking. If the chainline is too far off for all your gears to work, you might need a Lekkie wheel - @egroover found a cheaper alternative on aliexpress, there's a thread about it somehere. Also if your gear cables are brand new, they might stretch a bit initially. Too tight a chain could also cause problems.
 
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Russ34

Pedelecer
Oct 11, 2021
58
11
54
Teignmouth
Is it jumping like it wants to move to the next cog up? Or is it jumping off the smallest cog onto the axle? Maybe adjust the two adjustment screws on the derailleur? Or is it jumping in place on that smallest gear cog? Make sure zipties are not squeezing any of the gear cable sheaths. I replaced all of my gear cable sheaths, because they were sticking. If the chainline is too far off for all your gears to work, you might need a Lekkie wheel - @egroover found a cheaper alternative on aliexpress, there's a thread about it somehere. Also if your gear cables are brand new, they might stretch a bit initially.
Ah , the problem seems to be with the small cog so it could be alignment so I’ll have a look at the Lekkie Wheel , thanks for your help
 

guerney

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Sep 7, 2021
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Ah , the problem seems to be with the small cog so it could be alignment so I’ll have a look at the Lekkie Wheel , thanks for your help
Too tight a chain could also effect alignment, so I'd try a longer chain first and fiddle about some more, before spending on a Lekkie - if you message egroover, he might have a link to the cheaper alternative, which he reported back about a week ago, as being a good purchase.
 
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Jodel

Pedelecer
Oct 9, 2020
174
141
Some 'mystery' gear shifting issues can be caused by a misaligned derailleur hanger. It only takes a very minor degree of misalignment to cause shifting problems - although this tends to be across the whole cassette rather than a single gear.

If you don't have the correct tool to check alignment, a decent substitute can be an old hub/wheel screwed into the derailleur hanger.
 
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