There are a lot of reasons why your tire wears from the inside. What happens is, some of the suspension parts fail, therefore, causing the angle of the tire (camber) to slightly tilt which makes the inside of the tire have more contact with the road than the outside of the tire.
If your tire wears from the inside I will explain the 4 most common reasons why your tire wears from the inside and how to know exactly what’s causing it.
1. Negative Camber
Negative camber is when the inside of the tire is making more contact with the road than the outside of the tire causing your tires to wear on the inside. All tires should be set at an angle of 90 degrees to ensure equal tire wear. If your camber is negative, the angle of your tires would be less than 90 degrees and the tires would be slightly tilted inwards causing your tire to wear on the inside.
Many of the cars out there have non-adjustable camber from the factory. The car manufacturers do this they make all of the suspension components pre-set perfectly within spec.
The problem comes with wear and tear over time. Suspension components like bushings and ball joints become sloppy, the rubber gets old and dry and then it creates extra slop within the geometry of the suspension. The result of this is uneven tire wear or in this case, your tire wears on the inside.
The real fix for this would be to start replacing any worn-out bushings, ball joints, control arms, and other suspension parts. But the downside to that is it can get really expensive. So, it’s best if you look further into this issue and diagnose which suspension part has failed and is causing your tire to wear on the inside.
How To Measure Camber Angle on a Car
This is the easiest way to determine the camber angle on your car tires. If you determine that there is a difference in the measurements and your wheels have either a negative or positive camber, then you should take the wheel off and measure the angle with a spirit level.
- Park your car on a leveled ground. It is very important that your car is leveled. Use a spirit level to make sure that your car isn’t parked on unleveled ground.
- Set a plumb line so that it splits the wheel in half. The weight must hit neither the wheel nor the ground and should be at 90 degrees. The plumb line should be set on the bumper above the tire that you want to measure the camber on. You can use a spacer if necessary.
- With a measuring tape measure the distance between the plumb line and the upper outermost point of the rim.
- Then measure the distance between the plumb line and the lower outermost point of the rim.
- If you notice that the distance between the upper outermost point of the rim and the plumb line is different than the distance of the lower outermost part of the rim and the plumb line is different, your tire camber angle is off.
- Jack your car and remove the tire.
- Put a spirit level on the disks and you will be able to see the exact angle of your tire alignment. The angle should be 90 degrees, but if it’s off, you need to readjust it or your tires will continue to wear on the inside.
2. Worn Shocks and Struts
Shocks and struts are a part of the suspension system and have a function to absorb shocks caused by the road so your car doesn’t bounce a lot when you hit a pothole. Shocks and struts are installed at a specific angle, and they need to maintain that angle. However, worn-out shocks and struts can be bent and change their angle causing your tires to slightly tilt and wear on the inside.
The difference between the shocks and struts is that struts are basically a structural part of the vehicle that is installed on. Meaning, you can drive your vehicle without shocks, but you cannot drive your vehicle without a strut. Basically, the suspension would be sitting on the wheel. Being a structural part of the vehicle, worn-out struts can most definitely cause the tire to tilt inwards and cause your tire to wear on the inside.
Shocks and struts function off of the premise of turning kinetic energy into thermal energy. Essentially, you have a tube that is filled with a bunch of fluid and that is going to be pushed through a series of small holes called orifices inside by a piston. The orifices only allow so much fluid to travel through them at a given rate which is how you get your dampening that is going to control the movement of the car and the suspension.
How To Tell That Your Shocks and Struts Are Worn
Shocks and struts are often overlooked parts, but that doesn’t mean that they are not important. Shocks and struts can get damaged from a large pothole, corrosion from road salt, or simply wear. Here is how to tell that your shocks and struts are worn and need replacing:
- The most common sign that your shocks and struts are worn is when your tires wear faster than normal. Also, the wear on the tires occurs on one side, most of the time they wear on the inside.
- If the front of the car nosedives excessively when you press your brakes, your shocks and struts are worn and need replacing.
- If your car bounces more than usual when you drive over a pothole, your shocks and struts are worn and need replacing.
- Worn shocks and struts will often leak fluids and can be checked by a visual inspection or simply by pulling the rubber up and exposing the strut.
3. Worn Upper or Lower Ball Joints
Worn upper or lower ball joints can change how the tire of your car contacts the road. When upper or lower ball joints go bad, they affect the angle at which your tires sit on the road. Usually, they create a negative camber causing your tires to wear on the inside.
A ball joint is a connection that is flexible and it allows movement of the two parts of that connection in more than one direction at the same time. Basically, the ball joints allow the wheels to turn left and right and move up and down.
Each front tire has an upper and lower ball joint. The lower ball joint is attached to the lower steering knuckle at the wheel. The upper ball joint is attached to the upper steering knuckle.
Ball joints have a critical function in vehicle suspension because. Simply put, the ball joints hold the wheel to the car. The ball joints provide the suspension with the ability to move up and down when the tire hits a pothole.
When a ball joint becomes worn, the ball inside the socket or the socket itself wears out. If it’s bad enough, it can cause the tire to tilt inwards and wear on the inside. If you didn’t catch a bad joint on time, over time the ball joint can get so bad that your tire could completely come off.
How To Check If Your Ball Joints Are Bad
- If your upper or lower ball joints are bad your tires will wear n the inside. So, a great way of checking if your ball joints are bad is by looking at the tire wear.
- A worn upper or lower ball joint will make a squeaky noise (like an old door opening) when you turn the steering wheel or your suspension moves. You can either roll down the windows when you drive. Or, you can simply turn the steering wheel while your car is parked.
- You can visually inspect the upper and lower ball joints. See if the boots to the ball joints are cracked. A cracked boot will allow dirt and water to get in and cause a lot of trouble. The boots are non-greaseable and need to be replaced.
- Jack your car off the ground. Then grab your tire by the 12 and 6 positions (the upper and bottom part of the tire). Wiggle the tire back and forth. If your ball joints are worn, there would be play.
- Grab a crowbar or some type of long bar and place it under the tire. Then, move it up and see If there is any movement, clicking, or clunking noise. There should be no upward and downward motion in a ball joint. So, if you feel any movement or hear any noise, your upper or lower ball joints could be worn-out.
4. Bent Control Arms
Control arms can bend or break when the wheel of the car hits a curb or drives over a large pothole. Many modern cars have control arms made from poor material. It is not a newsflash for a control arm to bend or break upon hitting a curb.
Some vehicles have are equipped with four ball joints; two uppers and two lower. Front suspension systems with four ball joints are called SLA or short-long arm. But in most cases, strut equipped vehicles have only two lower joints.
A bent or broken control arm can affect the camber angle of your tire. The bent broken control arm can pull the tire inwards and causing it to wear on the inside.
Control arms should be stiff and free of play to best serve their purpose. Once the control arms or the bushings on the control arms become worn, there is an excess play and can cause the tire to tilt inwards and wear on the inside. The purpose of the bushing is to allow the control arm to twist and move up and down while absorbing impacts from the road.
Signs of a Bad Control Arm
- Worn tires on the inside.
- Instability while driving. If the control arm and the bushing are completely worn and have broken off, steering will become unpredictable and dangerous. Your vehicle may randomly pull to one side while you are trying to drive straight. Usually, the side to which the vehicle turns is the side the control arm is worn.
- Knocking or clunking noise while driving. When the bushing on the control arm is worn, the control arm will make knocking or clunking noise while driving, turning, braking, or going over small bumps on the road. This means that the rubber component of the control arm bushing is worn and causes metal to metal contact.