Right Handed Lockrings

Many, many years ago it was standard practice to convert your road bike to fixed for winter training by simply unscrewing the freewheel, screwing on a sprocket and shortening the chain. No lockring. Rest of the bike remained so 2 brakes stayed on. Never had a problem with this, or even saw it as a problem.

How times change :-)

Many (only slightly older) riders I know did this, and thought that's how I'd 'fix' my bike. They did see the problem and most used lockrings (bottom bracket ones). Some say don't use a lockring so if your chain gets jammed the sprocket unscrews instead of locking up your back wheel.

Do it right, a new wheel with fixed/free hub, cog and lockring fitted, can be had for ~£60.