The lower control arm bushings can wear and crack, resulting excessive movement at the control arm pivot point, leading to irregular and premature tire wear. Worn Ball joints can also cause similar tire wear symptoms. I some cases it may be necessary to replace the lower control arm, including bushings & ball joint to correct this concern.Google+
Car Problem Reports
Mercedes-Benz SL500 Premature Tire Wear Due to Cracked Lower Control Arm Bushings
Mercedes-Benz SL500 Problem
Average Mileage: 45,080 mi (23,000 mi - 58,000 mi)
Ok, this is my third problem for a "me too". I've not had this fixed yet.
Visitor, 2003 Mercedes-Benz SL500, 45,000 mi
no observed problem except tire wear - diagnosed at a service by distributor.