How to Read Tractor Tire Sizes and their Metric Equivalent

How to Read a Tractor Tire Size
- Locate your tire size on the sidewall of the tire (see picture above).
- The first number(16.9) represents the tire width sidewall to sidewall in inches.
- The second number(30) represents the rim diameter in inches.
How to Read a Metric Tractor Tire Size
Metric Size Conversion Example: Tire Size – 280/85R24
Metric Tractor Tire Size Conversion
- Locate your tire size on the sidewall of the tire.
- The first number represents the overall WIDTH when mounted and inflated to the proper air pressure but it is measured in millimeters. Divide this number by 25.4 to convert to inches. This will become the second number for a traditional tractor tire size.
- The second number represents the aspect ratio to the width of the tire (a percentage)HEIGHT when mounted and inflated to proper air pressure but is measured in millimeters. To convert this number to a traditional (inches) tire size, you multiple this number by 2 and divide by 25.4. Then add that number to the wheel diameter. This number now becomes the FIRST number in a traditional size.
- The “R” represents that the tire uses radial construction.
- The third number represents the diameter of the wheel this tire will mount on.
Standard, Radial, and Metric Tractor Tire Sizes
Tractor tire sizes can be written in many different formats. Sometimes you will see a size written like 11.2×24 or you may see it like 11.2-24. Use the table below to help you find radial tire size equivalents and metric conversions. If you have any questions, just give us a call at 1-800-225-9513, or email us.
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Tractor Tire Size Conversion Chart
Standard Size |
Radial Size |
Metric Size |
11.2X20 | 11.2R20 | 280/85R20 |
12.4X20 | 12.4R20 | 320/85R20 |
9.5X24 | 9.5R24 | 250/85R24 |
11.2X24 | 11.2R24 | 280/85R24 |
12.4X24 | 12.4R24 | 320/85R24 |
13.6X24 | 13.6R24 | 340/85R24 |
14.9X24 | 14.9R24 | 380/85R24 |
16.9X24 | 16.9R24 | 420/85R24 |
18.4X26 | 18.4R26 | 420/85R26 |
11.2X28 | 11.2R28 | 280/85R28 |
12.4X28 | 12.4R28 | 320/85R28 |
13.6X28 | 13.6R28 | 340/85R28 |
14.9X28 | 14.9R28 | 380/85R28 |
16.9X28 | 16.9R28 | 420/85R28 |
14.9X30 | 14.9R30 | 380/85R30 |
16.9X30 | 16.9R30 | 420/85R30 |
420/90R30 | ||
18.4X30 | 18.4R30 | 460/85R30 |
12.4X32 | 12.4R32 | 320/85R32 |
12.4X34 | 12.4R34 | 320/85R34 |
14.9X34 | 14.9R34 | 380/85R34 |
16.9X34 | 16.9R34 | 420/85R34 |
18.4X34 | 18.4R34 | 460/85R34 |
20.8X34 | 20.8R34 | 520/85R34 |
12.4X36 | 12.4R36 | 320/85R36 |
13.6X36 | 13.6R36 | 340/85R36 |
13.6X38 | 13.6R38 | 340/85R38 |
14.9X38 | 14.9R38 | 380/85R38 |
16.9X38 | 16.9R38 | 420/85R38 |
18.4X38 | 18.4R38 | 460/85R38 |
20.8X38 | 20.8R38 | 520/85R38 |
18.4X42 | 18.4R42 | 460/85R42 |
20.8X42 | 20.8R42 | 520/85R42 |
20.8X46 | 20.8R46 | 520/85R46 |
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