what's this little screw on my Brompton for?

[jay clock]

On the underside of the rear right chain stay there is tiny boss with a little allen bolt recessed into it? It is on an S3L so 3 speed hub. Just curious

 

[raleighnut]

Is it for the cable for the 2 speed rear cog mech (To turn it into a 6 speed)

 

[mickle]

It's the attachment point for the Brompton derailleur with which your bike is not equipped.

 

[jay clock]

OK! it looked like a little oil hole which did strike me as odd