The quintessential difference between riding freewheel or fixed is that with a freewheel cog there is a bearing that allows the back wheel to rotate free from the movement of the pedals & chain, and allows riders to stop pedaling at any point of the ride to cruise and enjoy their momentum. On the contrary, fixed gear cogs intentionally lack the bearing that separates wheel movement from drivetrain movement, meaning the pedals move in a fixed sync with the rear wheels. Ultimately, you cannot coast while riding fixed, your pedals continue to move with the rotation of the bike. For a further details anaysis, check out our Riding A Fixed Gear blog post.