Enter the tire sidewall height (in) and the tire width (in) into the Tire Aspect Ratio Calculator. The calculator will evaluate and display the Tire Aspect Ratio.
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Tire Aspect Ratio Formula
The following formula is used to calculate the Tire Aspect Ratio.
TAR = SH / W
- Where TAR is the Tire Aspect Ratio (height:width)
- SH is the tire sidewall height (in)
- W is the tire width (in)
To calculate the tire aspect ratio, divide the tire sidewall height by the tire width.
How to Calculate Tire Aspect Ratio?
The following example problems outline how to calculate Tire Aspect Ratio.
Example Problem #1:
- First, determine the tire sidewall height (in).
- The tire sidewall height (in) is given as: 12.
- Next, determine the tire width (in).
- The tire width (in) is provided as: 15.
- Finally, calculate the Tire Aspect Ratio using the equation above:
TAR = SH / W
The values given above are inserted into the equation below and the solution is calculated:
TAR = 12 / 15 = .8 (height:width)
FAQ
What is the significance of the Tire Aspect Ratio in vehicle performance?
The Tire Aspect Ratio is crucial as it affects the vehicle’s handling, ride comfort, and appearance. A lower aspect ratio typically means a wider tire that can offer better traction and handling but may result in a harsher ride. Conversely, a higher aspect ratio indicates a taller sidewall, which can absorb road imperfections better, providing a smoother ride at the expense of some handling performance.
Can changing the Tire Aspect Ratio affect my speedometer reading?
Yes, changing the Tire Aspect Ratio without recalibrating the vehicle’s speedometer can lead to inaccurate speed readings. This is because the tire’s circumference changes with the aspect ratio, affecting how many revolutions the tire makes over a certain distance. A larger circumference (from a higher aspect ratio) means fewer revolutions per mile, potentially causing the speedometer to under-report speed, and vice versa.
How do I choose the right Tire Aspect Ratio for my vehicle?
Choosing the right Tire Aspect Ratio depends on your driving needs and preferences. For performance-oriented driving, a lower aspect ratio can provide better handling and responsiveness. For everyday driving where comfort is a priority, a higher aspect ratio may be preferable. It’s also important to consult your vehicle’s manufacturer recommendations, as using a significantly different aspect ratio from the original equipment can affect the vehicle’s performance and safety.
