Groan - on right turns

[Lawrence Bardfeld <LB6116@PITCAIRN.com>]

There's a groaning noise (sort of a low-pitched squealing from the 
tire) from the front passenger side of my car ('93 S4) as the steering 
wheel is turned sharply right (even if car is not moving).  Vehicle's 
got original wheels, no chafing apparent in wheel well; clearances 
seem all right.  Probable causes?  (No, the groaning doesn't emanate 
from any human occupant of the passenger seat nor, as far as I can 
tell, from any listers who have been subjected to my past stupid 
questions.)

Thanks,
Larry Bardfeld
LB6116@pitcairn.com