Slack chain

[Jimmy Welch]

Hi I've recently fitted a new chain , same length as old one , but when in lower gear there's is a heck of a lot of slack which is causing the chain to come off frequently especially on bumpy sections and when changing up to the big ring. My thoughts are the rear mech might not be working properly and needs adjusting or the front derailleur is not doing its job

 

[MichaelW2]

Clear pic of chain and rear mech in lowest gear...

 

[Jimmy Welch]

Clear pic of chain and rear mech in lowest gear...

View: https://youtube.com/shorts/nPxG4me_w6E?feature=share

 

[DCBassman]

Need to see it side on, can't tell from that angle what's happening.

 

[I like Skol]

Need to see clearly a picture of the rear mech from the side but initial thoughts are that the chain is too long. Did you remove any links from the new chain to make it the same length as the original (assuming the original wasn't too long).

 

[Ming the Merciless]

Needs an in focus photo from the chain side, showing it from all the way back at rear derailleur all the way to front if front chain rings.

 

[Jimmy Welch]

Need to see it side on, can't tell from that angle what's happening.

View: https://youtu.be/DYVDNjaa21s

 

[Ajax Bay]

You are showing the chain in small/small. Let's just have an in focus image of the rear derailleur from the right side (ie along the wheel axle) with the chain in small/small: static!! Like Skolly, snap assessment is chain too long. Then we can move to FD (just set up properly).
Edit: You should not be shifting up to large ring when in smallest sprockets: why would you?

 

[I like Skol]

Pictures and videos just keep showing anything except what I and others have asked to see.

 

[Cycleops]

Calculate your correct size here:
https://www.bergfreunde.eu/chain-length-calculator/

 

[Ajax Bay]

Correct length is when in large/large the RD points between straight down and 135 degrees.

 

[Paulus]

Hi I've recently fitted a new chain , same length as old one

If the old chain was a certain length, assuming that it was worn out, the new one should have the same amount of links, but it would be slightly shorter in length.
After checking this, is the rear derailuer working correctly? The tension on the chain should be taken up by the spring tension.

 

[Ajax Bay]

assuming that [the old chain] was worn out, the new one . . . would be slightly shorter

Yes, an inch shorter!

 

[fossyant]

Assuming the chain is the right length, you've possibly got a sticky freehub, or even stickey jockey wheels, so you need to check. Remove wheel and see if freehub spins OK, then see if the jockey wheels do. I've just had to lube an upper jockey on my MTB as it was sticking.

 

[Jimmy Welch]

How's this