Ah, I checked the plastic housing for the worn out unit. The O.D. is 57mm, but there are ribs and an inner ring that hold the crappy bearings they use. BUT, if you cut out the ribs and inner ring, the I.D. is 52mm! So, basically I can use the old plastic housing to make an exact shim for the ER 16 bearing - way better than the crappy replacement units.
BTW, I did find on
123Bearing.com they make sealed ball bearings with 1" I.D. and 2.25" O.D., and one has a external groove for a snap ring (to flange the bearing) but the bearing is $80 and doesn't lock down onto the shaft like the ER 16.
