scozim - I just went out in the garage looking for thick v/s thin cups - No luck in any real measurement BUT the cups made for the "caged bearings" were thinner in external width and did appear lighter in weight??? - cudak888 and Sheldon have it right - And I seem to have stumbled onto the right spindle when using the 70mm 5s-B on three cottered crank conversions using loose balls... Ya know... following these threads instead of going out and facing a cold ride is not so bad... But still... My old Fuji (Horse) is calling...