Tire Size Comparison Calculator
Use this calculator to compare your original tire specifications with a potential new tire size. Understand how changes in tire width, aspect ratio, and rim diameter can affect your vehicle's speedometer, ground clearance, and overall performance.
Original Tire Specifications
New Tire Specifications
Calculation Results
'; resultsHTML += '';
resultsHTML += '
';
resultsHTML += 'Original Tire (' + originalWidth + '/' + originalAspect + 'R' + originalRim + ')
'; resultsHTML += '- ';
resultsHTML += '
- Sidewall Height: ' + originalSidewallMM.toFixed(2) + ' mm '; resultsHTML += '
- Overall Diameter: ' + originalOverallDiameterMM.toFixed(2) + ' mm (' + originalOverallDiameterInches.toFixed(2) + ' inches) '; resultsHTML += '
- Overall Circumference: ' + originalCircumferenceInches.toFixed(2) + ' inches '; resultsHTML += '
- Revolutions per Mile: ' + originalRevsPerMile.toFixed(2) + ' '; resultsHTML += '
';
resultsHTML += '
';
resultsHTML += 'New Tire (' + newWidth + '/' + newAspect + 'R' + newRim + ')
'; resultsHTML += '- ';
resultsHTML += '
- Sidewall Height: ' + newSidewallMM.toFixed(2) + ' mm '; resultsHTML += '
- Overall Diameter: ' + newOverallDiameterMM.toFixed(2) + ' mm (' + newOverallDiameterInches.toFixed(2) + ' inches) '; resultsHTML += '
- Overall Circumference: ' + newCircumferenceInches.toFixed(2) + ' inches '; resultsHTML += '
- Revolutions per Mile: ' + newRevsPerMile.toFixed(2) + ' '; resultsHTML += '
';
resultsHTML += '
';
resultDiv.innerHTML = resultsHTML;
}
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box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
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color: #2c3e50;
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color: #34495e;
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.calculator-results ul {
list-style-type: none;
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margin-bottom: 15px;
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margin-bottom: 8px;
padding: 10px 15px;
border-left: 4px solid #3498db;
border-radius: 4px;
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border: 1px solid #e0e0e0;
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border-left: 4px solid #5cb85c; /* Green for specs */
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.tire-comparison-summary ul li {
border-left: 4px solid #f0ad4e; /* Orange for comparison */
}
@media (max-width: 600px) {
.calculator-form {
flex-direction: column;
}
.input-group {
min-width: unset;
width: 100%;
}
.calculator-form button {
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}
Comparison
'; resultsHTML += '- ';
resultsHTML += '
- Overall Diameter Difference: ' + diameterDifferenceMM.toFixed(2) + ' mm (' + diameterDifferenceInches.toFixed(2) + ' inches) '; resultsHTML += '
- Ground Clearance Change: ' + groundClearanceChange.toFixed(2) + ' inches '; resultsHTML += '
- Speedometer Difference: ' + speedometerErrorPercentage.toFixed(2) + '% '; resultsHTML += '
- When your speedometer reads 60 MPH, your actual speed will be: ' + speedometerReads60Actual.toFixed(2) + ' MPH '; resultsHTML += '
Understanding Your Tires: A Guide to Tire Width and Size Changes
Tires are a critical component of your vehicle, influencing everything from safety and handling to fuel efficiency and ride comfort. Understanding tire sizing is essential, especially when considering an upgrade or replacement. This guide, along with our Tire Size Comparison Calculator, will help you navigate the complexities of tire dimensions.
Decoding Tire Size Numbers (e.g., 205/55R16)
A typical tire size designation, like "205/55R16," provides three key pieces of information:
- Tire Width (205): This is the first number and represents the tire's width in millimeters, measured from sidewall to sidewall. In our example, the tire is 205mm wide. A wider tire generally offers more grip but can also increase rolling resistance and potentially affect steering feel.
- Aspect Ratio (55): The second number is the aspect ratio, expressed as a percentage. It indicates the height of the tire's sidewall as a percentage of its width. So, for a 205/55R16 tire, the sidewall height is 55% of 205mm. A lower aspect ratio means a shorter sidewall, often found on performance tires, providing better handling and a firmer ride.
- Rim Diameter (16): The "R" stands for radial construction (the most common type), and the final number is the diameter of the wheel rim in inches that the tire is designed to fit. In our example, it's a 16-inch rim.
Why Use a Tire Size Comparison Calculator?
Changing your tire size, even slightly, can have several implications for your vehicle. Our calculator helps you understand these changes before you make a purchase:
- Speedometer Accuracy: One of the most critical factors. If your new tires have a different overall diameter than your original ones, your speedometer will read incorrectly. A larger diameter tire will make your speedometer read lower than your actual speed, while a smaller diameter tire will make it read higher. This can lead to speeding tickets or misjudging distances.
- Ground Clearance: A larger overall tire diameter will increase your vehicle's ground clearance, which can be beneficial for off-roading or navigating rough terrain. Conversely, a smaller diameter will reduce it.
- Fender Clearance: Wider tires or tires with a significantly larger overall diameter might rub against your vehicle's fenders or suspension components, especially during turns or when the suspension compresses.
- Handling and Ride Quality: Changes in tire width and aspect ratio can alter your car's handling characteristics. A wider tire might offer more grip, but a lower aspect ratio can lead to a harsher ride due to less sidewall flex.
- Aesthetics: Many people change tire sizes for a different look, often opting for larger rims and lower profile tires.
- Fuel Economy: Significantly wider or larger diameter tires can increase rolling resistance and weight, potentially impacting your vehicle's fuel efficiency.
How to Use the Calculator
Our Tire Size Comparison Calculator is straightforward to use:
- Enter Original Tire Specs: Find the tire size information on your current tires' sidewall (e.g., 205/55R16) and input the Width (mm), Aspect Ratio (%), and Rim Diameter (inches) into the "Original Tire Specifications" fields.
- Enter New Tire Specs: Input the specifications of the new tire size you are considering into the "New Tire Specifications" fields.
- Click "Calculate": The calculator will instantly display detailed information for both tire sizes, including sidewall height, overall diameter, circumference, and revolutions per mile.
- Review Comparison: Crucially, it will show you the differences in overall diameter, ground clearance change, and the percentage of speedometer error, along with what your actual speed would be if your speedometer reads 60 MPH.
Important Considerations When Changing Tire Sizes
- Manufacturer Recommendations: Always check your vehicle's owner's manual or the sticker on your driver's side door jamb for recommended tire sizes. Deviating too far can void warranties or affect insurance.
- Load Index and Speed Rating: Ensure any new tire maintains or exceeds the original tire's load index and speed rating to ensure safety and performance.
- TPMS Recalibration: If your vehicle has a Tire Pressure Monitoring System (TPMS), changing tire sizes might require recalibration.
- Professional Advice: If you're unsure about a significant tire size change, consult with a professional tire technician or your vehicle manufacturer.
By using this calculator and understanding the implications of tire size changes, you can make an informed decision that enhances your vehicle's performance, safety, and appearance.