have been riding a homemade singlespeed for a while as a commuter and decided to make the jump to fix with a freewheel option through a flip flop hub. got an iro dark matter flip flop wheel to do the job.
i installed the wheel tonight on the fix side first, put my cog on first and the lockring as hand tight as possible, put the wheel in, tightened it down and perfection, fixie bliss.
then i flipped the wheel over after putting the cog on the free, non tapered side as tight as i could by hand it ran like a fix, the cranks kept spinning even when i wasn't pushing them on the stand. took it off the stand and rode it, same problem, only when riding, if i push back to try and coast the cog spins off the hub and the bike just quits.
what am i doing wrong here? i assume there is a simple fix, but iro gives you no directions and i can't find this problem on the web to get a solution. have i just not tightened the freewheel cog enough? i don't know, messed with it for an hour and decided to ask!
You need to install a freewheel cog, not a fixed cog. What you have are fixed cogs on both sides of your hub, regardless of threading. Therefore, you're currently running fixed/fixed.....even though your hub is a fixed/free.