Tie rods connect steering components on automobiles and trucks to the front wheels. The tie rod is fastened to the steering rack on one end and the wheel hub on the other. The tie rod pushes and pulls the wheel for turning. Tie rods also have adjustable length. Shortening and lengthening the tie rod adjusts the wheel's position in relation to the vehicle's frame and aligns the wheels correctly. A tie rod, however, is subjected to tremendous wear and exposed to the road. These circumstances can lead to a broken tie rod.
Every time you turn the steering wheel on your car or truck, you are subjecting both tie rods to tremendous stress. The fittings at each end bear the brunt of the torque exerted on the turning wheels. Bushings, fasteners and the tie rod metal can fatigue and fail. Constant vibration from road conditions also wears on the threading connecting the two tie rod sections.
The tie rod is a long threaded bolt screwed into a threaded tube. The end of each piece has a cast eye for attaching to the vehicle. The long threaded male section can fatigue and fail, causing the tie rod to bend and eventually break. The cast eyes for attaching the ends can also fatigue from the constant turning, pushing and pulling from the steering action.
The tie is behind the wheel and in the exposed wheel well. As such it has no protection from road hazards entering the wheel well and breaking the metal components. Whether brand-new or with hundreds of thousands of miles on the vehicle, a piece of metal, rock or wood can impact the tie rod and break either piece or both.
A common road hazard that will also break a tie rod is spent tire rubber ejected from recapped tires. Often seen on over-the-road highways used by commercial trucks, these bands of rubber litter the roads in some places when they become detached and fly off tires. When a large piece of the hard rubber gets pulled into the wheel well, it can wrap around the tie rod and then be pulled away if it rolls under the spinning wheel. The result is the tie rod snapping instantly.
Tie rod length is adjusted in or out to align the front wheels. Front wheels are aligned so there is no wobble or vibration when travelling in a straight line. Wheels out of alignment (often caused by impacting a speed bump or some other road hazard) can vibrate incessantly or have a very noticeable shake or wobble if severely out of alignments. The wheels moving constantly in this back-and-forth motion can wear the tie rod, connections, fastenings and bushing quickly. A brand-new tie rod attached to an unaligned wheel can deteriorate in a few hours of driving. The failure usually occurs where the tie rod is connected to the wheel.