Originally Posted by
CliftonGK1
Also gives you the most versatility for a flip-flop since you can run a freewheel or a fixed cog on either side. (Sure, you can run a fixed cog on both sides of a fixed/free hub, but you're sans lockring on one side.)
I use double stepped hubs that have a lock ring on both sides for a fixed and fixed set up and even on a conversion with horizontal drops you usually have room for a 3 tooth difference in cogs.
Although I could run a freewheel I prefer the fixed / fixed set up on all my bikes.