The most common type of steering system is the rack-and-pinion steering. In a rack-and-pinion system, the steering wheel turns a pinion gear that engages a linear rack. The rack moves back and forth as the pinion gear turns, pushing or pulling the tie rods connected to the wheels. This type of steering is used in most cars today because it provides good feel and precise control. Another type of steering system is recirculating ball steering. In this system, there are multiple balls that rotate between two tracks (called racks) as you turn the steering wheel. The inside track is attached to the inner tie rod and the outer track is attached to the outer tie rod. As you turn the wheel, the balls roll around in their tracks and push or pull on the racks, which ultimately steers the wheels. Recirculating ball steering is used in some trucks and SUVs because it can handle large loads without excessive wear on components. Hydraulic power assist systems are also used in some vehicles. These systems use hydraulic fluid pressure to help reduce driver input effort required to steerthe vehicle by amplifying turning force atthe roadwheels about an axis throughthesuspension geometry's roll centre .