Without knowing which specific part number hubs you're speaking of, it's hard to say what the differences are, but I can give some generalities that might help answer your question.
The specific hub you'll need will depend on the diameter of the spindle where the inner and outer bearings ride and the diameter of the spindle where the grease seal rides. The wheel size and axle capacity will also come into play as well.
For instance, the # 8-258-50UC1-EZ hub you'd looked at is rated for... view full answer...