Can Wrong Size Tires Damage A Transmission?

Manufacturing companies spend excessive resources determining the best size tires for your vehicle. Tire size is a crucial aspect for performance engineers as it greatly influences the overall functionality of your vehicle. Engineers determine the stock tire size that will provide your vehicle with an optimal amount of torque, acceleration, and safety. Despite the research done to discover the best size tire for a vehicle, individuals can still wish to change the size of the tires they use.

Wrong size tires do not damage the transmission. Although ill-fitting tires do not directly impact the transmission, it does impact the overall performance of the vehicle. Wrong size tires can cause a safety hazard as well as cause structural damage to the vehicle.

Although the wrong size of tires will not damage the transmission, what are the negative results of changing tire size? Below will explain everything you will need to know what it comes to having the wrong size tires.

Does Wrong Size Tires Damage Your Vehicle?

Wrong size tires can easily damage your vehicle. Vehicles are designed in a way that their stock tires are the best fit. Companies test their vehicles with tires that will ensure safety and longevity. The tires that provide an optimal performance eventually become the stock tires. Using tires that are the wrong size can put the driver and those around the vehicle in grave danger.

A common mistake is to purchase tires that do not fit simply because they are cheaper and are more aesthetically pleasing. Do not purchase the wrong size tires because they are less expensive or because they have a more lavish appearance.

When needing to replace your tires, try to match the width and aspect ratio to the stock tires.

Width Of Tires

The width of tires is oftentimes increased because individuals blindly follow the belief that the wider the tire, the more traction it provides. Therefore, individuals come to the conclusion that the performance of the vehicle must be optimized with wider tires. However, this is a common misconception. Before increasing the width of your tires, consider the suspension of your vehicle.

Increasing the width of your tires and not simultaneously changing the suspension could result in a vehicle that is far too difficult to handle. The wider tires could potentially make your vehicle unsafe to operate if the suspension is not modified as well.

In addition to making the vehicle difficult to maneuver, changing the width of your tires can result in your tires grinding various vehicle components. This can cause damage that is expensive or even result in the components needing to be replaced entirely.

Contact with the fender liner is the most common contact point with poorly fitted tires. The fender liner is the plastic barrier between the fender and the engine. Damage to the fender liner is vexing, however, it can be fixed fairly easily.

In addition to damaging the fender liner, damage to the strut and spring is also possible. If the new tire width is able to reach the strut and string, then damage can easily occur. Tires should never be able to reach these components and contact should be avoided at all costs. Severe damage can be done if the tires are able to reach the strut and spring in your vehicle.

Damage to the structure of the vehicle is also possible when the width of the tires is changed. Structural damage is more serious and exasperating than other types of damage.

Aspect Ratio Of Tires

Adding tire sidewall is another common tire size adjustment, especially from an aesthetic standpoint on trucks and SUVs. The taller sidewall profile adds an element of muscularity to the side view of the wheel, and the vehicle as a whole. Even a small bump in vehicle ride height can be achieved with an aspect ratio upsize.

As with an increase in tire width, increasing the sidewall height of the tire is not without potential hazards.

Interior suspension components are generally not in the crosshairs, but the fender liner and connecting body panels above, in front of, and behind the tire can be contact points.


What Happens With The Wrong Size Tires

Now that we know wrong size tires can damage the structure of your vehicle, what exactly can happen if the tires do not fit properly? How do too large and too small of tires impact the overall performance of your vehicle?

Tires That Are Too Large

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Manufacturers recommend not to replace tires that have more than a 2-inch difference compared to the original stock tires. Even tires that are within 1-inch of the original tires have the potential to cause damage. If the tires are too large, it will limit the amount of space available under the arches. Large tires will appear more aesthetic as they will fill the arches, however, the suspension in the vehicle will be inhibited. When driving over uneven roads, the suspension system is meant to absorb the impact. However, if the tires are too large, then they will hit the inside of the wheel arch.

If your tires are too large, the inside walls will rub against the wheel wells and will cause damage to the body of the vehicle as well to the walls of the tires. This could result in the tires causing severe damage in a matter of months.

If your tires happen to be too large, then the fuel efficiency is sure to go down. Larger tires are heavier and have a higher rolling resistance. Because of the increased weight and resistance, the fuel efficiency lowers.

In addition to having a lower fuel efficiency, larger tires can cause less stability. Larger tires cause the center of gravity to shift, which results in a loss of control. This can become a safety hazard for drivers and passengers. If your tires are too large, then you will not be able to brake and turn corners at high speeds as you could in the stock tires.

The larger the tires, the less control you have over your vehicle. Larger tires make vehicles more difficult to maneuver, which can lead to an increase in accidents. In addition, because larger tires are more vulnerable to bending, the vehicle will not run as smoothly on regular roads.

Although it is possible to put larger tires on a vehicle, it is not recommended to do so. Doing so could put too much weight upon the wheel assembly. Stress that could otherwise be avoided will impact the fuel efficiency as well as the brakes. Too large of tires can rub against the body of the car and will grind until there is a vast amount of damage.

If you do wish to increase the size of your tires, remember the following checklist:

  • Stay within the manufacturer recommended size increase (1-2″) so if you have 16″ rims, don’t go bigger than 18″
  • Make sure there’s enough clearance in the wheel arches to turn full lock (both ways) and go over bumps
  • If you go wider and they are protruding out the side of the arches, they are probably too big
  • Check tire prices on your new tire size
  • Go lightweight (if you can) Source: FremontMotors

Tires That Are Too Small

Tires that are too small do have their benefits. The following are some of the pros to having smaller tires:

  • Allows your engine to exert more torque per revolution
  • Increase in fuel efficiency
  • Increase of stability at high speeds
  • Reduction in aerodynamic drag
  • Reduction in noise
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One of the largest benefits of decreasing the size of tires is better mileage. While it is true that smaller tires increase fuel efficiency, the drawbacks of smaller tires are so significant that manufacturers do not recommend downsizing.

Tires that are too small negatively impact the speedometer. Speedometers measure your speed by keeping track of the number of tire revolutions in your vehicle. However, speedometers are programmed to larger stock tires. Because of this, the speedometer will be inaccurate as smaller tires do not go the same distance with the same number of tire revolutions. This will result in the speedometer saying your vehicle is going faster than it actually is.

More than one computer or sensor on just about anything on four wheels today requires an accurate and constant idea of how far and fast a vehicle is traveling. Most get this from wheel speed sensors, meaning if you put the wrong sized tires on a vehicle, the speed/distance data will be inaccurate.

This can lead to checking engine lights, transmission shifting troubles, anti-lock brake malfunctions, along with a possible long list of problems. On certain vehicles, it can even cause a stall of the engine, which will not restart.


In addition, smaller tires raise the final drive ratio of your vehicle. Increasing the final drive ratio will result in more torque but a lower top speed. A higher final drive ratio will increase the acceleration.

Tires that are too small can cause many disturbances in your vehicle and can cause malfunctions that could otherwise be avoided.

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