I've recently bought a sturmey-archer AW hub from ebay to install on my bike instead of derailleurs (I may yet go hybrid by retaining the triple crank or installing two sprockets, but that's another matter.) I have all the bits- hub, sprocket, shifter, cable, adjuster, but I'm unsure how to route the shift cable. Most of the 3 speed bikes I've seen have a clamp-on fitting on the chainstay to secure the end of the cable housing. Being a mountain bike, my bike doesn't have that.
Is it a bad idea to simply run the cable housing to the stop on the downtube, and route the cable along the downtube and under the bottom bracket?