I just put NTN 32203 bearings in my big swing arm.
They are 40 x 17 x 17.25 basically the same size as oe.
I was able to use the original outer dirt seal from the previous bearings. It isn't a perfect seal, but at least the bearings can now be greased via the pivot bolts.
How much of an issue is greasing the bearings?......perhaps not too much as my bearings were 31 years old. They were stuffed, but still quite serviceable.
Lord of the Bings, kangaroo farmer