Brompton chain coming offage problem

[Yellow Fang]

I have a problem with my Brompton: the chain tends to come off when I unfold it. Has anyone else ever had this problem, and if so, how did they solve it?

 

[ChrisKH]

I have never had this directly - which model do you have and how many miles has the chain done?

 

[Yellow Fang]

I have an L3. I don't think the chain is all that worn. It was replaced about six months ago and it hasn't done an awful lot of mileage since.

 

[stevew]

Check the chain tensioner's spring tension to see if it moves freely but with a good amount of tension. If it's sticky it may not be following the chain when the bike is folded.

 

[rob_mcp]

I borrowed one which did this - but never got to the bottom of it. I suspect that stevew may be right It seemed particularly prone to this if I knocked the pedal back while unfolding it
My own has never done this

 

[Yellow Fang]

It hasn't been doing it recently, but I haven't cycled it all that much. I suspect that either the chainwheel or the derailleur wasn't screwed in very tightly.