Posted for Tubamanflies@aol.com:

 Matt,
 
 Check for dragging brakes or tight bearnings.  Both will kill a tire very
 quickly.
 
 Possible toe in fixes.  None of with I have tried.
 
 1. Shim the axle where it meets the casting.
 2. Shim the casting were it meets the gearleg, Outback  gear.
 3. New GM5 rear attach plate.
 
 Again these are just ideas.  I have not had the opertunity to try them.
 
 Ray Gardner