Make sure the back rims are on square.  There are 2 (10mm) bolts in the rear
drums that need to be removed for most alloy rims.  If not the alloy rims
will wobble back and forth (ask me how I witnessed this in the last couple
of months).  GOWESTY told me to remove them when I bought their rims a year
and a half ago. I forgot it when I had a SA rims and new tires put on a van
last month.  Something just wasnt right.  I looked in the side mirror and
saw the back wheel wobbling.  At first I thought it was a bent rim.  I
looked at the pax side mirror and that side was wobbling also.  Then I
remembered the bolts.....  I forgot to tell the tire store about them.

John
Vanaru.com