resizing array devices not working?

I was trying to do a little experiment with resizing devices.  I created two 1g logical volumes and built a raid1 array out of them, then lvresized the volumes to 2g, then ran:

mdadm -G -z max /dev/md1

That SHOULD expand the array to use the extra space right?  It keeps telling me that it set the size to just 1g.