Originally Posted by hyperRevue
Not quite.
Fixed = single speed that can't coast
Single speed = can coast
Flip/flop hubs are just hubs with two sides of threads, either free/free, fixed/free or fixed/fixed.
Fixed hubs have two sets of threads, one for the fixed cog and one for the lockring, which is a safety mechanism designed to prevent the fixed cog from spinning off the hub.
Freewheel cogs can be used on fixed hubs but fixed cogs cannot be used on SS hubs, since there are no threads for lockrings.
Hope that helps.
true true I always think of flip flops for all my biking needs, but that can be set up many differing ways.