.02mm ~ 8 ten thousandnths of an inch. or (0.00079")

bearing design hasn't really changed that much, from when my father was a machinist int eh 70's through early 90's.

Material and application have defiently improved. But typically the better applciation process is applied to the newer "old" bearings on the market today.

When you tear your motor down, you will have to mic out your crank journals, install the main bearings and use a bore gagues to determine what they meaure. Then do some simmple math and determine if the added 8 ten thousandths keep you within factory spec or more importantly what range you would like to run.

Another thing to think about is are the bearings you replacing a known issue?