Originally Posted by jeremywhitehorn
it would seem that the spacer / cog set up is even less fussy than a SS specific hub. the other cog would just slip on the freehub as a spacer does. maybe the experts here could comment on this but i would imagine that running a derailleur as a tensioner would be a great choice as you wouldn't have to worry about chainline...
I can't see a problem with using two cogs with spacers. If it was one chainring I would set the 2 cogs a little off center of it so the chain line would be a little off with both, but nothing severe. Not nearly the chainline issues with s/s as there is with fixed. The tensioner should have enough lateral movement to work. A deraileur would work no problem. I would still make sure I had non-ramped chainrings and cogs even with a tensioner. Other option is to do like Sirrobin did, do a double chainring/double cog. Either both on the inner with spacers and long CR bolts, or one on the inner/outer. Should work with a mtb crank. Would still work with a s/s specific hub, mine is made to be used with spacers, I just threaded a cog on instead. Can't get it off now, but that's not the issue.