Sturmey Archer 3 speed chain keeps unscrewing?

[BromptonNewbie1]

Hi! I've had a Brompton for a few months now and the whole time there has been an issue with the gears. I took it to a repair guy who said the Sturmey Archer 3 speed chain was missing (which he replaced with the one in the pic). With it in place, it does work but will keep unscrewing itself (as in the big rod part is two parts that screw together). If I screw it up all the way tight, the gears don't work and it still gradually unscrews itself - I have to keep adjusting it to be halfway screwed in.

I would just take it back to the repair guy as I'm a complete newbie, but I have warantee from Brompton and if this is a bigger issue I will save my money and bring it up with them instead.

Any advice hugely appreciated! But just keen to know if this is a big weird issue or something obvious that I'm missing. Google hasn't helped

David

 

[gbb]

If I understand your problem correctly, all you have to do is adjust the gears so they work correctly, then importantly nip up that circular knurled nut probably with a pair of pliers or similar, against the female cable end. It might be that that's coming loose allowing the adjuster chain to turn and put your gears out of adjustment

 

[gbb]

YouTube has some good, simple videos on how to adjust them. They will, or should, end with locking that knurled nut up.

 

[Cycleops]

Locktite?

 

[biggs682]

Once the gear adjustment is set and they work you could try a blob of paint on the knurled wheel and it's thread.

I have done thousands of miles with same set up and never had one come loose

 

[simongt]

Indeed. with the 3 speed adjuster you've illustrated, once you've found the correct adjustement length, it's important to keep the knurled nut tight against the barrel adjuster screw or it will unscrew during normal use as it's usually under tension. You can do this with a pair of pliers as suggested, but my experience is simply to make it well finger tight.
Works for me.

 

[BromptonNewbie1]

This is all really helpful thank you!!!! I love forums you are all fantastic and so knowledgeable. Will follow your advice.

 

[tyred]

I've ridden thousands of miles on various three speed bikes and have always found finger tightness adequate for doing up the locknut. If they had considered tools necessary they would have made it square or hexagonal rather than just knurled IMO.

 

[Tenkaykev]

Link to the Brilliant Bikes guide:-


View: https://www.youtube.com/watch?v=-mGfuqxilO4&t=7s

 

[EltonFrog]

There are different length gear indicator rods, are you certain you have the correct one.

 

[gbb]

Tbf, Tyred's comment re the lack of need for tools is correct, its been decades since I had a SA shod bike .





Just make sure its tight in essence.

 

[biggs682]

There are different length gear indicator rods, are you certain you have the correct one.

You would like to think so

 

[classic33]

Why was the toggle chain missing in the first place, if you bought it new.

Is the axle turning in the rear dropouts?

 

[BromptonNewbie1]

Why was the toggle chain missing in the first place, if you bought it new.

Is the axle turning in the rear dropouts?

IKR! Puzzled the repair guy too. Gears worked fine at first but I think the toggle chain was put on wrong and unscrewed itself and then fell off. No idea what the rear dropouts are xx

Will take the bike back to the repair guy and make sure it is the right size rod and get it calibrated and screwed up right, thanks all