not op, but I have this problem with my bmx bike. I was using it to commute and began to hear a squeaking noise from the rear wheel. the squeak turned into a grind which turned into a crunch before seizing completely. I pulled the wheel off and the freewheel seems to be in working order, but the axle won't turn at all. is it possible to get new bearings for a hub the same way that you can get new bearings for a bottom bracket or head tube?