It is not uncommon for wheels on these vehicles to be very easily bent or otherwise damaged, often to the point of requiring replacement. This can happen even with no apparent damage to the tire.Google+
Car Problem Reports
Mitsubishi Eclipse GSX Wheels may easily be bent or damaged
Mitsubishi Eclipse GSX Problem
Visitor, 1998 Mitsubishi Eclipse GSX, 89,000 mi
Rims are very soft, and dents interfere with accurate balancing. Replacing rims - go with a remanufactured rim.