This is a modern cheaper equivalent of the original bearing that are very hard to get and expensive.

This bearing is slightly wider than the original bearing

To compensate for this, we supply them with a new bearing spacer/seat that is pushed into the hub.

Using these parts ensures all dimensions are correct. 

Please remember that these bearings should not be packed solid with grease, the rollers have to be able to push the grease out of the way.

Failure to observe this will shorten the life of the bearing.

Correctly lubricated they should last a lifetime.