5/45R9 Tire Size Calculator
Complete specifications and dimensions for 5/45R9 tire size
5/45R9 Quick Specifications
How to Read 5/45R9 Tire Size? What Does 5/45R9 Mean?
Let's break down the tire size 5/45R9 to understand what each number and letter means:
5 (Section Width)
The first number "5" represents the tire's width in millimeters, measured from sidewall to sidewall. In this case, the tire is 5 millimeters wide (approximately 0.20 inches).
45 (Aspect Ratio)
The number "45" after the forward slash is the aspect ratio or profile. This means the tire's sidewall height is 45% of its width. For a 5mm wide tire, the sidewall height would be2.25mm (approximately 0.09 inches).
R (Construction)
The letter "R" indicates this is a Radial tire, which is the most common type of tire construction today. Radial tires have layers of cord that run radially (at 90 degrees) from the center of the tire.
9 (Wheel Diameter)
The last number "9" specifies the wheel diameter in inches. This means the tire is designed to fit a 9-inch wheel. The total diameter of the tire would be the wheel size plus twice the sidewall height.
Detailed Measurements for 5/45R9
Based on the 5/45R9 tire size, here are the calculated measurements:
- Total Tire Diameter: 9 inches (wheel) + 2 × 0.09 inches (sidewall height) = 9.18 inches
- Sidewall Height: 2.25mm or 0.09 inches (on each side)
- Circumference: Approximately 28.83 inches (based on π × total diameter)
- Revolutions per Mile: About 2198 (varies slightly based on load and air pressure)
Key Tire Measurements Explained
Section Width
The width of the tire from sidewall to sidewall, measured in millimeters. For 5/45R9, this is 5mm or approximately 0.20 inches.
Aspect Ratio
The height of the tire's sidewall as a percentage of the width. A 45 aspect ratio means the sidewall height is 45% of the tire's width.
Overall Diameter
The total height of the 5/45R9 tire when mounted on the wheel is 9.18 inches. This includes both the wheel diameter and the tire's sidewall height on both sides.
Sidewall Height
For 5/45R9, the sidewall height is 2.25mm (0.09 inches). This is the distance from the wheel rim to the outer edge of the tire.
Why Accurate Tire Measurements Matter
- Vehicle Performance: Tire size affects your vehicle's acceleration, braking, and handling characteristics.
- Speedometer Accuracy: Changes in tire diameter can affect your speedometer and odometer readings.
- Clearance Issues: Incorrect tire sizes may cause rubbing against your vehicle's fenders or suspension components.
- Fuel Economy: Larger or heavier tires can impact your vehicle's fuel efficiency.
Pro Tips for 5/45R9 Tires
✓ Check Your Vehicle's Manual: Always consult your vehicle's manual to confirm 5/45R9 is the correct size for your vehicle.
✓ Consider Your Usage: The 5/45R9 size may be better suited for specific uses (highway driving, off-road, performance, etc.).
✓ Maintain Proper Sizing: Keep front and rear tire sizes consistent unless specifically recommended otherwise by your vehicle manufacturer.
✓ Watch for Clearance: When using 5/45R9 tires, ensure adequate clearance for steering, suspension, and body components.
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