[ChuckDickerson]

Originally Posted by Greg Needel

A couple of reasons:
*since these are thin they require both spacers and another bearing(in the sprocket) for sprockets to be used with a dead axle. The old plastic ones don't require either of these so their installation is cleaner.

*People have been prototyping using the plastic ones and if they like their drive the way it is I doubt they will just abandon those for un-tested waters.

*people also might have purchased wheels before these came out and want to use inventory.

Basically they are both great products and people will have to choose for themselves which they care to use.

Good points, Greg!