Originally Posted by
3alarmer
PB Blaster it, let it sit for a while (15 minutes, maybe), remove both crank arms, put the whole bike up in a bench vise with soft jaws (copper or aluminum), the vise should
be grasping the non drive side spindle taper. Take a hammer and drift (or a chisel, if you can throw away this lock ring and use a different one) and strike it forcefully and with great vigor with the drift in each of the notches as described by FB. You need to angle the drift so that your force goes tangential to the BB, not radial, in the counter clockwise direction.
Curse if you need to.
Your description relates to a bottom bracket lockring removal. The OP said the bike is a fixie so I believe his problem is the lockring on the rear hub. Also, if it is the hub lockring, is he aware it's left hand threaded.