When you turn the steering wheel on your car, truck, van, or SUV, you set quite a few parts into motion, hopefully ending with the tie rod and ball joint at each of your front wheels. Though they work together, the tie rod and ball joint are two separate entities that make sure your car can steer left and right at the same time it's hitting bumps that might cause the wheel to travel up and down. That's easier said than done. To be effective, your steering system has to turn the wheels at the same rate and along the same plane no matter what the conditions, and the tie rod and ball joint are there to see to it that the wheels are held steady. Let's start with the tie rod: As its name suggests, the tie rod ties together your steering rack or parallelogram linkage and your steering knuckle (the part your wheel is attached to). Most cars have an inner tie rod and an outer tie rod on each side of the vehicle so that the linkage has two pivot points. The tie rod can be permanently lubricated or it may have a grease zerk for periodic lubrication. Regardless of which kind you have, the tie rod will fail eventually, resulting in loose, sloppy steering. As for the ball joint, it lives between the steering knuckle and the A-arm. Your car may have just an upper ball joint or an upper and a lower ball joint per side. The ball joint holds the steering knuckle firmly in place as your wheel bounces up and down and turns from side to side. Like a tie rod, the ball joint is often greasable but it does wear out over time due to the stresses placed on the front suspension system. A loose, worn ball joint can cause significant handling problems since it basically results in you having a loose wheel. Clunking noises, wandering, and overall poor handling are signs of a bad ball joint as well as a bad tie rod. Pay attention to your tires, too: A worn suspension component, like a tie rod and/or ball joint, often results in abnormal wear patterns on your tires. By keeping an eye on the tread, looking for cupping, scalloping, and heavy wear, you can spot a bad ball joint or tie rod long before it becomes dangerous to you and your passengers.