.tyre-calculator-comparison-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 25px;
background: #f9f9f9;
border-radius: 10px;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
color: #333;
}
.tyre-calculator-comparison-container h2,
.tyre-calculator-comparison-container h3 {
color: #2c3e50;
text-align: center;
margin-bottom: 20px;
}
.tyre-calculator-comparison-container .input-group {
display: flex;
flex-wrap: wrap;
gap: 15px;
margin-bottom: 20px;
justify-content: center;
}
.tyre-calculator-comparison-container .input-section {
flex: 1;
min-width: 300px;
background: #fff;
padding: 20px;
border-radius: 8px;
box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}
.tyre-calculator-comparison-container .input-section label {
display: block;
margin-bottom: 8px;
font-weight: bold;
color: #555;
}
.tyre-calculator-comparison-container .input-section input[type="number"] {
width: calc(100% – 20px);
padding: 10px;
margin-bottom: 15px;
border: 1px solid #ccc;
border-radius: 5px;
font-size: 16px;
box-sizing: border-box;
}
.tyre-calculator-comparison-container button {
display: block;
width: 100%;
padding: 12px 20px;
background-color: #3498db;
color: white;
border: none;
border-radius: 5px;
font-size: 18px;
cursor: pointer;
transition: background-color 0.3s ease;
margin-top: 20px;
}
.tyre-calculator-comparison-container button:hover {
background-color: #2980b9;
}
.tyre-calculator-comparison-container .results-section {
margin-top: 30px;
background: #eaf4f9;
padding: 25px;
border-radius: 8px;
border: 1px solid #cce7f4;
}
.tyre-calculator-comparison-container .results-section h3 {
color: #2c3e50;
margin-bottom: 15px;
text-align: left;
}
.tyre-calculator-comparison-container .results-section table {
width: 100%;
border-collapse: collapse;
margin-bottom: 20px;
}
.tyre-calculator-comparison-container .results-section th,
.tyre-calculator-comparison-container .results-section td {
border: 1px solid #ddd;
padding: 10px;
text-align: left;
}
.tyre-calculator-comparison-container .results-section th {
background-color: #d6eaf8;
font-weight: bold;
color: #333;
}
.tyre-calculator-comparison-container .results-section td {
background-color: #fefefe;
}
.tyre-calculator-comparison-container .results-section .comparison-summary p {
font-size: 1.1em;
margin-bottom: 10px;
line-height: 1.6;
}
.tyre-calculator-comparison-container .results-section .warning {
color: #e74c3c;
font-weight: bold;
margin-top: 15px;
}
.tyre-calculator-comparison-container .article-content {
margin-top: 40px;
line-height: 1.7;
color: #444;
}
.tyre-calculator-comparison-container .article-content h3 {
color: #2c3e50;
margin-top: 30px;
margin-bottom: 15px;
text-align: left;
}
.tyre-calculator-comparison-container .article-content p {
margin-bottom: 15px;
}
.tyre-calculator-comparison-container .article-content ul {
list-style-type: disc;
margin-left: 20px;
margin-bottom: 15px;
}
.tyre-calculator-comparison-container .article-content li {
margin-bottom: 8px;
}
function calculateTyreComparison() {
var currentTyreWidth = parseFloat(document.getElementById('currentTyreWidth').value);
var currentAspectRatio = parseFloat(document.getElementById('currentAspectRatio').value);
var currentRimDiameter = parseFloat(document.getElementById('currentRimDiameter').value);
var newTyreWidth = parseFloat(document.getElementById('newTyreWidth').value);
var newAspectRatio = parseFloat(document.getElementById('newAspectRatio').value);
var newRimDiameter = parseFloat(document.getElementById('newRimDiameter').value);
// Check for valid inputs
if (isNaN(currentTyreWidth) || isNaN(currentAspectRatio) || isNaN(currentRimDiameter) ||
isNaN(newTyreWidth) || isNaN(newAspectRatio) || isNaN(newRimDiameter) ||
currentTyreWidth <= 0 || currentAspectRatio <= 0 || currentRimDiameter <= 0 ||
newTyreWidth <= 0 || newAspectRatio <= 0 || newRimDiameter 3) {
speedometerImpactText = "Warning: The overall diameter difference is " + overallDiameterDiff.toFixed(2) + "%. This is outside the recommended +/- 3% range and will significantly affect your speedometer accuracy and potentially your ABS/traction control systems. ";
if (overallDiameterDiff > 0) {
speedometerImpactText += "Your speedometer will read lower than your actual speed (e.g., if your speedometer reads 100 km/h, you'll be going faster).";
} else {
speedometerImpactText += "Your speedometer will read higher than your actual speed (e.g., if your speedometer reads 100 km/h, you'll be going slower).";
}
document.getElementById('speedometerImpact').className = 'warning';
} else if (Math.abs(overallDiameterDiff) > 0.5) {
speedometerImpactText = "The overall diameter difference is " + overallDiameterDiff.toFixed(2) + "%. This is within acceptable limits, but your speedometer will have a slight deviation. ";
if (overallDiameterDiff > 0) {
speedometerImpactText += "Your speedometer will read slightly lower than your actual speed.";
} else {
speedometerImpactText += "Your speedometer will read slightly higher than your actual speed.";
}
document.getElementById('speedometerImpact').className = ";
} else {
speedometerImpactText = "The overall diameter difference is " + overallDiameterDiff.toFixed(2) + "%. Speedometer accuracy should be minimally affected.";
document.getElementById('speedometerImpact').className = ";
}
var widthDiff = ((newTyreWidth – currentTyreWidth) / currentTyreWidth) * 100;
var diameterDiffMM = Math.abs(newOverallDiameter – currentOverallDiameter);
if (widthDiff > 10 || diameterDiffMM > 20) { // Arbitrary thresholds for potential rubbing
clearanceWarningText = "Caution: The new tyre is significantly wider (" + widthDiff.toFixed(2) + "%) or has a notably different overall diameter (" + diameterDiffMM.toFixed(2) + " mm difference). There is a higher risk of rubbing against fenders, suspension, or brake components. Always check for clearance before driving.";
document.getElementById('clearanceWarning').className = 'warning';
} else {
clearanceWarningText = "The width and overall diameter differences appear to be within reasonable limits for clearance, but always perform a physical check after installation.";
document.getElementById('clearanceWarning').className = ";
}
generalAdviceText = "Always consult your vehicle's owner's manual or a professional tyre specialist before changing tyre sizes to ensure compatibility and safety.";
document.getElementById('speedometerImpact').innerHTML = speedometerImpactText;
document.getElementById('clearanceWarning').innerHTML = clearanceWarningText;
document.getElementById('generalAdvice').innerHTML = generalAdviceText;
document.getElementById('tyreComparisonResult').style.display = 'block';
}
Tyre Size Comparison Calculator
Compare your current tyre specifications with a potential new size to understand the impact on your vehicle's performance and speedometer accuracy.
Current Tyre (e.g., 205/55R16)
New Tyre (e.g., 225/45R17)
Comparison Results
| Metric | Current Tyre | New Tyre | Difference (%) |
|---|---|---|---|
| Tyre Width | |||
| Aspect Ratio | |||
| Rim Diameter | |||
| Sidewall Height | |||
| Overall Diameter | |||
| Circumference | |||
| Revolutions per km |
Understanding Tyre Sizing and Comparison
Tyres are a critical component of your vehicle, influencing everything from safety and handling to fuel efficiency and speedometer accuracy. Understanding tyre sizing and how different sizes compare is essential, whether you're replacing worn tyres, upgrading your wheels, or simply curious about your vehicle's specifications.
How to Read a Tyre Size (e.g., 205/55R16)
A typical tyre size designation, like 205/55R16, breaks down into three key measurements:
- 205 (Tyre Width in mm): This is the nominal width of the tyre's tread in millimeters, measured from sidewall to sidewall. A wider tyre generally offers more grip but can also increase rolling resistance.
- 55 (Aspect Ratio in %): This number represents the height of the tyre's sidewall as a percentage of its width. In this example, the sidewall height is 55% of 205mm. A lower aspect ratio means a shorter sidewall, often found on performance tyres, offering better handling but potentially a harsher ride.
- R16 (Rim Diameter in inches): This indicates the diameter of the wheel rim the tyre is designed to fit, measured in inches. 'R' stands for Radial, the most common tyre construction type.
Why Compare Tyre Sizes?
Changing your tyre size, even slightly, can have several implications:
- Speedometer Accuracy: A different overall tyre diameter will alter how many revolutions the wheel makes per mile/kilometer. If the new tyre's diameter is larger, your speedometer will read lower than your actual speed, and vice-versa.
- Fender Clearance: A larger overall diameter or width might cause the tyre to rub against the wheel wells or suspension components, especially during turns or over bumps.
- Ride Comfort and Handling: A lower aspect ratio (shorter sidewall) typically provides sharper handling and better cornering stability but can lead to a firmer ride. A higher aspect ratio offers more cushioning and a smoother ride.
- Gearing and Performance: A significant change in overall diameter can effectively alter your vehicle's final drive ratio, impacting acceleration and fuel economy.
- Aesthetics: Many enthusiasts change tyre and wheel sizes for a specific look.
How This Calculator Works
This calculator takes the standard tyre sizing inputs for both your current and a potential new tyre. It then calculates the following key metrics for each tyre:
- Sidewall Height: The actual height of the tyre's sidewall in millimeters.
- Overall Diameter: The total height of the inflated tyre from top to bottom, in millimeters.
- Circumference: The distance covered by one full rotation of the tyre, in millimeters.
- Revolutions per km: How many times the tyre rotates to cover one kilometer.
Finally, it compares these metrics between your current and new tyre, showing the percentage difference. This helps you quickly assess the impact of a tyre size change, particularly on speedometer accuracy and potential clearance issues.
General Guidelines for Tyre Changes
Most experts recommend keeping the overall tyre diameter within a +/- 3% difference from the original equipment (OE) size. Exceeding this range can lead to significant speedometer errors, ABS/traction control system malfunctions, and potential rubbing issues. Always consult your vehicle's manufacturer recommendations or a professional tyre specialist before making significant changes.