cheap 3-speed drum brake

If we're talking about the hub only, then it doesn't seem particularly inexpensive to me. But it doesn't seem like a bad price, either.

An internally geared hub plus drum brake does seem like an intriguing idea for an MAB, doesn't it?

The question I've always had over it is will that drum brake interfere with mounting the engine drive sprocket? I'd have to find the answer to that before I could give it a try.

But imagine a motor bike with drum brakes front and rear. It does sound nice.

I've got a Sturmey Archer SRC 3 that I'd be willing to sell. Got it to do an 'upgrade' to my bike. The MB spocket side of the hub would require some creative engineering to make the spocket fit.....it's got a pretty large diameter.

With that being said, I'd take offers if someone would like to attempt using it (It is used, but in great condition.) With the drum brake, you cannot use a jackshaft set up.

Actually what's in the picture is a coaster brake, its basically a drum type brake but activated by pedaling backward hence the reason its useless on a jack shafted bike where the front sprocket freewheels.

The actual drum brake hubs use a 70 or 90 mm drum on the left side of the hub actuated by a pull cable. These would work on a shifter setup but one would have to fab a large sprocket to connect to the right side making it impractical to use where the engine input on the right side since the hole in the sprocket would have to be bigger than the drum brake assembly not to mention the limited space for the lever arm.

So basically... no coaster brake for shifters and no drum brake when the driven sprocket needs to be installed on the right hand side.

SA used to make a 3 speed hub with a cable operated drum brake because my 1952 Hercules has one. One problem with them though is overoiling the hub leads to oil getting on the brake shoes.