There is a bearing cross-reference search on the SKF website; unfortunately it is only available to select members of the domain. The user must log in with the correct credentials in order to use the cross-reference search engine.
The SKF website specifically states that the bearing comparison tool is only meant to be used by selected SKF representatives. Even so, the system is used to compare and describe what type of bearings can fit on non-SKF assemblies. The information found on the tool only reveals information on bearings that can replace non-SKF bearings, but does not enclose any details in regards to replacing SKF bearings with other aftermarket units.