If you’ve raised or lowered your vehicle, chances are you need a camber kit to correct your camber. Camber is the angle off the vertical that your tire sits at. Ideally, you should have between one and two degrees of negative camber on your wheels. This means the top of your wheel should lean toward the centerline of the car. Extreme lowering of your car increases this negative camber by pulling down and in on your wheels and tires. Extreme body lifts tend to do the opposite, pushing the tires out at the top. A camber kit corrects this. Exactly what you get in the kit depends on what type of suspension you have and how much change you need to impart.
For more info, see 5 Tips for Buying a Lowering Kit