Picking the correct tractor tyre size is essential for traction, stability, and long-term performance. Whether you’re upgrading, replacing, or configuring tyres for different tasks, this tractor tyre size chart will help you make fast and informed decisions.
Understanding Tractor Tyre Sizes
Tractor tyre sizes are written in both standard (imperial) and metric formats. Each number in the size represents tyre width, aspect ratio, construction type, and rim diameter.
For example, let’s break down 16.9-28:
- 16.9 = Tyre width in inches
- 28 = Rim diameter in inches
- – = Bias construction (R indicates radial if present)
A metric example like 420/85R30 means:
- 420 = Tyre width in millimetres
- 85 = Aspect ratio (sidewall height is 85% of width)
- R = Radial construction
- 30 = Rim diameter in inches
To match your front and rear tyres for 4WD tractors, use the
4×4 Tractor Tyre Ratio Calculator to avoid drivetrain issues.
Tractor Tyre Size Chart
This chart includes common tractor tyre sizes for 2WD, MFWD (Mechanical Front Wheel Drive), and rear-wheel drive configurations.
| Imperial Size | Metric Equivalent | Tyre Position | Rim Diameter |
|---|---|---|---|
| 6.00-16 | – | 2WD Front Tyre | 16 in |
| 7.50-16 | – | 2WD Front Tyre | 16 in |
| 9.5-24 | 240/85R24 | MFWD Front Tyre | 24 in |
| 11.2-24 | 280/85R24 | Rear Tyre (Compact) | 24 in |
| 12.4-28 | 320/85R28 | Rear Tyre (Utility) | 28 in |
| 13.6-28 | 340/85R28 | Rear Tyre | 28 in |
| 14.9-28 | 380/85R28 | Rear Tyre | 28 in |
| 16.9-30 | 420/85R30 | Rear Tyre (Field Tractor) | 30 in |
| 18.4-34 | 460/85R34 | Rear Tyre (Row Crop) | 34 in |
| 20.8-38 | 520/85R38 | Rear Tyre (High HP) | 38 in |
Why Does Tyre Size Matter?
Using the wrong tyre size can lead to poor traction, uneven wear, and even damage to your tractor’s driveline. This is especially true for 4WD and MFWD machines where tyre ratios must be carefully matched.
Before changing tyre sizes, always verify them using the 4WD Tractor Wheel Ratio Calculator.
Tyre Sizing and Ballast Weight
Heavier or wider tyres often need additional ballast to maintain traction and balance. A properly ballasted tractor not only performs better but also reduces tyre wear.
To calculate the right amount of ballast based on your tyre size, try the Ballast Calculator for Tractor Tyres.
Tips for Choosing the Right Tractor Tyre Size
- Match your tyre size to the rim diameter and width
- Stick to manufacturer-recommended sizes for best results
- Use radial tyres for comfort and field performance; use bias-ply for rugged conditions
- Balance tyre pressure based on load and field conditions
- Never mismatch front and rear tyres on 4WD tractors without checking ratios
Also, if you’re running a business or contracting work, you can estimate your job costs more accurately with the Hourly Rate for Tractor Work Calculator.
Transporting Tractors with Larger Tyres
Larger tyres can affect the height and angle required for safe loading onto trailers. If the ramp angle is too steep, you risk bottoming out or tipping the machine.
Use the Garden Tractor Ramp Calculator to find the right ramp size for your tyre height and trailer.
Conclusion
Whether you’re dealing with compact tractors or high-horsepower machines, tyre sizing is a key part of safe and effective operation. The wrong size can hurt traction, increase fuel use, and damage your drivetrain.
Use the chart above as a quick reference, and rely on helpful tools like:
- 4×4 Tyre Ratio Calculator
- 4WD Wheel Ratio Calculator
- Ballast Weight Calculator
- Hourly Rate Calculator
- Ramp Calculator
Choose the right tyre size for your needs and work smarter with every field pass.