Brompton Fold: Chain slack

[berylthebrompton]

Hello.

I have noticed since degreasing and cleaning my chain/sprockets the other day that when I crank the pedals backwards the chain goes slack and clatters against the frame. I initially thought the pully wheels were stiff so used to GT85 on them, but it seems to be the same. I notice it most when trying to get the right pedal in the correct position during the fold - but now I am aware of it I sometimes hear it when I am stationary and raise the pedal ready to set off.

View: https://youtu.be/tzmT20es0-g


Its about 2 months old. If its normal and I have just missed it then please let me know!

 

[chris folder]

Hi what make of chain lube did u use? sounds like the chain links have gone sort of sticky where they was lose links before. i was going to lube my chain wheels other day but brompton dont say they need lube/oil on them? Maybe because there plastic But a llittle should be ok. I would keep look on the area where chain is tapping as frame will soon start to scuff there. May I ask is that a 6 speed brompton? If so do you here a whirling sound not as ququite as high gears when your in 1st and 2nd gears? Say when going up hills if rideing where background noise u will not hear it it in quite areas do u hear the sound from 1st and 2nd?

 

[Rohloff_Brompton_Rider]

A well known issue on new 6 speeds. The plastic disc causes friction which isn't a problem in 1,2,4 or 5th. In 3 and 6th the additional internal hub friction over rides the chain tensioner Spring power and as such when hurtling down hills the chain will sag dangerously close to the rear wheel. Clicking into 1,2,4 or 5th lets the chain tensioner pull the chain tight again.

Basically what I'm saying is avoid 3 and 6th downhill freewheeling or when folding. It does get better when it wears in.

 

[berylthebrompton]

A well known issue on new 6 speeds. The plastic disc causes friction which isn't a problem in 1,2,4 or 5th. In 3 and 6th the additional internal hub friction over rides the chain tensioner Spring power and as such when hurtling down hills the chain will sag dangerously close to the rear wheel. Clicking into 1,2,4 or 5th lets the chain tensioner pull the chain tight again.

Basically what I'm saying is avoid 3 and 6th downhill freewheeling or when folding. It does get better when it wears in.

Thanks for the explanation!

 

[Kailash Elmore]

I'm experiencing the same thing on my 3 speed (which is around 10 years old and serviced about once a year).
I use dry conditions lube and have cleaned the chain tensioner but it's still clanking against the frame when in top gear and not cycling.
I took apart the chain tensioner and regreased the little wheels but there's the sagging chain clanking against the frame.
Any ideas?

 

[Rohloff_Brompton_Rider]

I'm experiencing the same thing on my 3 speed (which is around 10 years old and serviced about once a year).
I use dry conditions lube and have cleaned the chain tensioner but it's still clanking against the frame when in top gear and not cycling.
I took apart the chain tensioner and regreased the little wheels but there's the sagging chain clanking against the frame.
Any ideas?

Read above

 

[Kailash Elmore]

I have done. But the chain links are clean as so am still a bit stumped as to the cause.

 

[Rohloff_Brompton_Rider]

Nothing to do with chain links.