Most drivers ask this question when the damage has already been done: “What Causes Uneven Tire Wear?” This inconvenience is not only dangerous, but it can also be costly. Tires are an extremely important component of your car. Therefore, it’s important that you check them periodically to see how they’re faring. If you’re not exactly sure what causes tire wear or what to look out for, read on to learn about the common causes of wear on the inside and outside edge of your tires.

Causes Of Uneven Tire Wear On The Outside Edge

1. Wheel Misalignment

Wheel misalignment is one of the most common causes of tire wear on the outside edge. If your vehicle was involved in a major accident or hit a large pothole while you were driving, you may begin to experience this issue. Wear on the tire’s outside edge occurs when the wheel tilts on the outside and starts putting more pressure on the road-facing shoulder of the tire. Over time, it will cause the rubber on the tire’s outer edge to scrub faster than the one on its inner edge. 

Therefore, it’s important to check the alignment of your tires every 6,000 to 7,000 miles. Additionally, be sure to decrease the time between successive alignment check-ups once the suspension and wheels get older.

2. Bent Spindles Or Struts

Struts or spindles form an essential structural component of most vehicles’ suspension. They join the dampening impact of the shock absorber with the upper ball joint and hold the wheel and tire assembly in place. Their optimum performance is also necessary to maintain ride comfort. Most of the time, the top of the strut is rotated to get optimal camber and correct wheel alignment. When that specific part is bent, the entire setting misaligns. This causes the wheel to misalign and the front tires to start wearing on their outside edge. The magnitude of the tire wear will be dependent on how much (or how little) the spindle has bent.

The good news is that if the damage to the spindle isn’t too severe, the tire wear may be reversible and less costly to repair. However, if the spindle has bent beyond repair, it will have to be replaced

3. Sagging Springs

Sagging springs help support a vehicle’s entire weight and absorb excess energy that emanates from road shocks. Their anti-sway bar is responsible for shifting the movement of the wheels and, in turn, stabilizing the car. However, the application of constant load on the springs will weaken their flexibility over time. This results in either the leaf spring losing arch or the coil spring losing height. In either case, it will be important to replace the springs that may have sagged.

4. Worn Ball Joints

Ball joints are another crucial component of your car’s front suspension. Their work involves maintaining the tire’s optimum contact with the road throughout the motion of the suspension. They also control arms to provide a vibration-free ride and give you full control over your vehicle.

Similar to other parts in your vehicle, ball joints are prone to wear and tear. As they start to show signs of damage, your car’s wheels will slightly point outward. Mechanics refer to this condition as the ‘toe’ of the wheel going out of alignment.

Tire wear caused by worn-out ball joints is hard to notice but it is no less dangerous than one caused by wheel misalignment. Both end up placing more pressure on the outer edge of the tire and may lead to the tire wearing on the outside. To rectify this, it is best to replace the worn-out ball joints and have the front wheels realigned. But if the problem still persists, you may also have to change the control arm.

Causes of Uneven Tire Wear On The Inside Edge

1. Incorrect Camber Angles

Camber refers to the angle of the wheel and tire relative to a perfectly flat road. Positive camber reduces steering effort and provides greater stability in a straight line, while negative camber occurs when a tire faces inward toward the vehicle. In the case of inner tire wear, negative camber is often to blame.

When a vehicle exhibits negative camber, the front tires will wear on the inside as this portion of the tire makes a greater degree of contact with the road’s surface. The same can also be said when rear tires wear on the inside edge. This typically occurs on a vehicle that features a 4-wheel independent suspension.

2. Incorrect Toe Angle

Toe is defined as the angle of a vehicle’s tires in relation to one another, or the center axis of a vehicle. This angle can be observed when standing in front of a vehicle while looking at the leading edge of both tires. A “toe-in” condition is evident when both tires appear to be pointing inward toward one another. Conversely, “toe-out” is evident when tires appear to face outward.

A vehicle that exhibits a substantial degree of toe-out will often show accelerated wear on the inside edge of its tires. This is because the inner segment of each tire is essentially being pulled across the pavement. As a result, the tread compound is prematurely eaten away on the portion of the tire that has been forced to absorb the highest amount of friction.

3. Worn Ball Joints

In the case of accelerated inner tire wear, worn lower ball joints are often the culprit. Ball joints use a ball and socket type design to secure a vehicle’s control arms to its steering knuckles. As a ball joint begins to age, normal friction causes this ball and socket to become loose and display a certain degree of free play. This free play allows unintended outward movement of the steering knuckle itself, thereby having the same effect on its corresponding tire. Without proper maintenance, a worn lower ball joint can change a vehicle’s camber angle to the point of causing inner tire wear.

4. Worn Control Arm Bushings

Control arms serve as the connecting link between a vehicle’s chassis and steering knuckles. Both upper and lower control arms are fitted with rubber or elastomer bushings at their pivot points along a vehicle’s chassis. The purpose of these bushings is to prevent excess free play that can adversely affect camber angles. As control arm bushings age, they begin to slowly deteriorate. This deterioration causes uneven tread wear often eating away at the tire’s inside tread.

5. Worn Or Damaged Suspension Components

A vehicle’s struts and springs absorb road vibration and the shock associated with encountering the occasional pothole. These components also play a vital role in maintaining a vehicle’s stock ride height. This set ride height directly impacts a vehicle’s camber angles, which has the potential to cause less than satisfactory tire wear when compromised. 

As vehicles age, its springs tend to sag causing a reduction in the vehicle’s ride height. Additionally, notable impacts of any kind can lead to strut tower lean, which can result in out-of-spec camber adjustment. Correcting such concerns generally require component replacement or the shimming of affected springs.

Visit Vancouver Axle and Frame for Vehicle Maintenance Service

Checking and maintaining your tires is a critical part of keeping yourself and your vehicle safe. If you’re concerned about uneven tire wear on your vehicle, we can help. Vancouver Axle & Frame is a full-service repair facility serving the Fraser Valley, BC. Contact us today to schedule an appointment with one of our certified technicians.