I offered to clean up a bike for a friend, and encountered this freewheel. It doesn't seem to have internal splines.
Quick google leads me to believe I need an obsolete lockring tool. Is this true?
Honestly, I don't think this bike is going to be ridden—friend thinks they
might ride it next spring, but they've had the bike for a least a decade, and I'm guessing it's been ridden maybe ten times. So I could just leave it, but the bearings feel a little crusty.
EDIT:
False alarm, it does have splines, and a Park FR-1 fits. Duh!
MF-HG20 Shimano freewheel