Axle adjustment in Atom drum brake? I have a tandem with a drag brake in the hub of the back wheel.  It works perfectly, providing a steady drag when descending.

QUESTION: Can I simply treat it like a normal rear wheel with cups/cones, and adjust the axle, or do I have to be careful of the drum brake's innards? 

Details:


ABOVE: Drive side of axle - there is 4.5 mm of thread exposed, plus 1.5 mm of cambered slope.


ABOVE: Left side of axle, showing barely 1mm of axle through the nut and the visible bit is not threadded.


Left side view - showing drum brake arm and reaction arm.

I wish to fit this trailer hitch, which goes on the left side of the rear wheel axle.  It is 3 mm thick plate.
Answer Yes its a standard cup and cone axle.

I had to unbolt the reaction arm from the chainstay, and unbolt the brake cable from the activation lever arm.  This was simple.

Gotchas though - you have to remove the drum brake completely, and the inside cone is recessed so its hard to get a cone spanner on it.  Best method is to get the inner cone and lock nut in the right place on the axle, and tighten them together and then do the drive-side cone.

Hub with locknut and spacer removed.  Notice there's an awful lot of spoke holes on this thing, I could fit double the number of spokes!  :


Drum/hub with brake removed::


Drum shoes, view from the inside.  They're not a great fit with some parts worn smooth and other parts never touched the drum.  Activation is incredibly simple-the shorter arm is pulled forward by a brake cable, which rotates the shaft.  There are lobes on the shaft that push the brake shoes apart, and against the inside of the drum.  When the cable pull drops, the two beefy springs pull the shoes back off the drum.