This project has been on and off my work stand for about two years now and it's finally road worthy. It's really not meant to be practical but is more of an excercise in "can it be done?" First I have to thank Rudi "rhm" and the Sturmey Ninja, Dallas "photogravity" for being great resources for all things IGH. Dallas even contributed the SRAM 24T cog. Also, the benevolent spirit of Sheldon Brown, from whose writings the idea originally sprang. He mentions somewhere on his site that Shimano cassette cogs can be modified to fit on Sturmey-Archer hubs.
I decided to try to make a 2-range/3-speed drivetrain for 6 total speeds. I wanted to leave off derailleurs because this is going to be a winter errand bike and it will see slush and icy conditions. One cog is a SRAM, made for IGH use, and one is a Shimano which has had most of the splines ground off to fit the Sturmey-Archer 3-spline pattern.
The gearing is 38-14 on "high" range and 28-24 on "low" range. The low/low is ridiculously low (about 23") because I live on a steep hill and I want to climb it easily with a load in less-than-ideal conditions. High range is 98", 73" and 55". The number of teeth wrapped is the same on both ranges (52) but because the cogs have different tooth profiles, the chain tension is not consistent. That, plus the need to hand-shift is why I added the chain tensioner to the mix. It is not very elegant but it will have to do. I could buy a tensioner that mounts to the derailleur hanger but I'm too cheap and this one was in the parts bin. I considered using Sturmey wing nuts on the rear axle to move the axle each gear change to regulate the tension, but again, I'm too cheap and it seems too fussy.
Enough talking, enjoy a few pics.