Q: Why does the factory Model S wear its inner rear tires?

From the factory the Model S lacks rear camber adjustability, which leads to premature inner tire wear. The Billet Adjustable Rear Camber Arm Set in this package fixes that by letting you remove or add camber, so you can dial the rear back toward a tire-friendly setting or add negative camber for handling. Correcting camber, especially after lowering the car, is the key to even rear tire wear and longer tire life.