I'm having trouble finding replacement rear 42T steel sprocket. The biggest I've found is 40T. Anyone know of a source, I've tried Sprocket Specialists and a bunch advertising in magazines, but no cigar. Even a blank is acceptable, I can machine the bolt pattern and open the bore. The sprocket I'm replacing is bare aluminum but didn't seem to last very long, maybe 11k miles. Do the hard coated anodized sprockets last longer? TIA