body {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: #f8f9fa;
color: #333;
line-height: 1.6;
margin: 0;
padding: 0;
}
.loan-calc-container {
max-width: 800px;
margin: 30px auto;
padding: 30px;
background-color: #ffffff;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}
h1, h2 {
color: #004a99;
text-align: center;
margin-bottom: 20px;
}
.input-group {
margin-bottom: 20px;
display: flex;
flex-wrap: wrap;
align-items: center;
}
.input-group label {
flex: 1 1 150px;
min-width: 150px;
margin-right: 15px;
font-weight: bold;
color: #004a99;
}
.input-group input[type="number"] {
flex: 2 1 200px;
padding: 10px 15px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 1rem;
}
.input-group span.unit {
margin-left: 10px;
font-weight: bold;
color: #555;
}
button {
display: block;
width: 100%;
padding: 12px 20px;
background-color: #004a99;
color: white;
border: none;
border-radius: 5px;
font-size: 1.1rem;
cursor: pointer;
transition: background-color 0.3s ease;
}
button:hover {
background-color: #003366;
}
#result {
margin-top: 30px;
padding: 20px;
background-color: #e9ecef;
border-radius: 8px;
text-align: center;
border: 1px solid #dee2e6;
}
#result h3 {
margin-top: 0;
color: #004a99;
font-size: 1.4rem;
}
.result-value {
font-size: 2.5rem;
font-weight: bold;
color: #28a745;
display: block;
margin-top: 10px;
}
.result-note {
font-size: 0.9rem;
color: #6c757d;
margin-top: 10px;
}
.article-section {
margin-top: 40px;
padding-top: 20px;
border-top: 1px solid #e9ecef;
}
.article-section h2 {
text-align: left;
margin-bottom: 15px;
}
.article-section p, .article-section ul {
margin-bottom: 15px;
}
.article-section ul {
padding-left: 20px;
}
.article-section li {
margin-bottom: 8px;
}
@media (max-width: 600px) {
.input-group {
flex-direction: column;
align-items: flex-start;
}
.input-group label {
margin-bottom: 8px;
flex-basis: auto;
}
.input-group input[type="number"] {
width: 100%;
flex-basis: auto;
}
.input-group span.unit {
margin-left: 0;
margin-top: 8px;
}
h1 {
font-size: 1.8rem;
}
.result-value {
font-size: 2rem;
}
}
Understanding Rim and Tire Sizes
Choosing the correct rim and tire size is crucial for vehicle performance, safety, and aesthetics. This calculator helps you understand the relationships between different tire dimensions and how they affect your vehicle's overall tire diameter. Proper tire sizing ensures accurate speedometer readings, optimal handling, and prevents potential clearance issues.
The Math Behind Tire Sizing
Tire dimensions are typically expressed in a standardized format, such as P225/50R17. Let's break down what each number means and how it relates to the overall tire diameter:
- Tire Section Width (e.g., 225 mm): This is the width of the tire from sidewall to sidewall in millimeters.
- Aspect Ratio (e.g., 50%): This represents the tire's sidewall height as a percentage of its section width. So, a 50 aspect ratio means the sidewall height is 50% of 225 mm.
- Rim Diameter (e.g., 17 inches): This is the diameter of the wheel (rim) that the tire is designed to fit.
Calculating Tire Sidewall Height:
Sidewall Height (mm) = Tire Section Width (mm) * (Aspect Ratio / 100)
For example, with a 225 mm width and a 50 aspect ratio:
Sidewall Height = 225 mm * (50 / 100) = 225 mm * 0.50 = 112.5 mm
Calculating Tire Diameter in Inches:
To get the total tire diameter, we need to consider the sidewall height on both the top and bottom of the rim, and convert it to inches.
- Total Tire Width (mm): Tire Section Width + (2 * Sidewall Height)
- Total Tire Width (inches): Total Tire Width (mm) / 25.4 (since 1 inch = 25.4 mm)
Using our example:
Total Tire Width = 225 mm + (2 * 112.5 mm) = 225 mm + 225 mm = 450 mm
Total Tire Width in Inches = 450 mm / 25.4 ≈ 17.72 inches
This 17.72 inches is the overall diameter of the tire.
Calculating Diameter Difference:
The calculator also shows the difference between a newly specified tire and a reference (new) tire diameter. This is important for ensuring your speedometer remains accurate. A significant difference can lead to incorrect speed readings and potentially affect vehicle systems that rely on wheel speed.
Diameter Difference (%) = 100 * ((New Tire Diameter – Original Tire Diameter) / Original Tire Diameter)
Why Use This Calculator?
- Upgrade/Downgrade Wheels: See how changing rim size affects your tire's overall diameter.
- Performance Tuning: Understand how tire diameter impacts gearing and acceleration.
- Speedometer Accuracy: Estimate the impact of new tire sizes on your speedometer readings.
- Visual Appearance: Gauge how different tire profiles might change the look of your vehicle.
- Clearance Checks: While this calculator doesn't directly measure clearance, understanding diameter is a first step.
Always consult your vehicle's owner's manual and consider professional advice when making significant changes to your tire and rim setup.
function calculateTireSize() {
var tireWidth = parseFloat(document.getElementById("tireWidth").value);
var aspectRatio = parseFloat(document.getElementById("aspectRatio").value);
var rimDiameter = parseFloat(document.getElementById("rimDiameter").value);
var newTireDiameterInput = parseFloat(document.getElementById("newTireDiameter").value);
var calculatedTireDiameter = document.getElementById("calculatedTireDiameter");
var diameterDifference = document.getElementById("diameterDifference");
calculatedTireDiameter.textContent = "–";
diameterDifference.textContent = "–";
if (isNaN(tireWidth) || isNaN(aspectRatio) || isNaN(rimDiameter)) {
alert("Please enter valid numbers for Tire Width, Aspect Ratio, and Rim Diameter.");
return;
}
// Calculate Sidewall Height in mm
var sidewallHeightMM = tireWidth * (aspectRatio / 100);
// Calculate Total Tire Width in mm
var totalTireWidthMM = tireWidth + (2 * sidewallHeightMM);
// Calculate Total Tire Diameter in inches
var totalTireDiameterInches = totalTireWidthMM / 25.4;
calculatedTireDiameter.textContent = totalTireDiameterInches.toFixed(2);
// Calculate Diameter Difference if new tire diameter is provided
if (!isNaN(newTireDiameterInput)) {
var diffPercentage = 0;
if (!isNaN(totalTireDiameterInches) && totalTireDiameterInches > 0) {
diffPercentage = 100 * ((newTireDiameterInput – totalTireDiameterInches) / totalTireDiameterInches);
}
diameterDifference.textContent = diffPercentage.toFixed(2) + "%";
} else {
diameterDifference.textContent = "N/A";
}
}