5kCSTQW: Wearing inside edges of front tires

[steveb@newkla.kla.com (Steven Buchholz)]

I went to rotate my tires from front to back on the '88 5kCSTQW last
night.  I found that the inside edges of both front tires were worn 
significantly more than the rest of the tires.  Back tires look as I 
would expect.  I had a 4-wheel alignment done when I replaced the 
steering rack about 9 months ago.  What can cause this type of wear
pattern?

TIA 
Steve Buchholz
s_buchho@kla.com