There isn’t a single tire size for every 2009 A4 model. The factory sizes vary by trim and wheel package, but you’ll commonly see sizes from 205/55R16 up to 235/45R17 and 245/40R18.
Why size varies by trim and wheels
Audi offered multiple wheel and tire configurations for the 2009 A4, including different wheel diameters and performance packages. The exact size on your car depends on the original equipment when it rolled off the lot. To confirm the precise size for your vehicle, check the door jamb sticker and the owner's manual, or consult Audi’s official documentation for your specific trim and market.
Common factory sizes by wheel option
The following listings reflect typical stock tire sizes you may encounter on a 2009 A4 in common US-market configurations. Use this as a guide, but verify your car’s exact size before purchasing tires.
- 16-inch wheels: 205/55R16
- 17-inch wheels: 235/45R17
- 18-inch wheels: 245/40R18
Note: Some markets or packages may use slightly different sizes (for example, 225/50R17 or 255/40R18 on specific configurations). Always confirm the exact size from your vehicle’s documentation or the tire sidewall.
How to confirm the exact tire size on your car
To determine the precise OE tire size for your particular 2009 A4, use these steps:
- Inspect the tire sidewall for the size code, such as P205/55R16 91V, which shows width, aspect ratio, and diameter.
- Check the driver’s door jamb sticker where the vehicle’s recommended tire sizes are listed for front and rear wheels.
- Refer to the owner’s manual for the original equipment tire specifications for your trim and market.
- When replacing tires, aim to match the OEM size and, if upgrading, discuss options with a qualified tire professional to maintain appropriate speed rating and load index.
In practice, sticking with the OEM size ensures proper speedometer accuracy, braking performance, and ABS/ESP behavior. If you’re considering upgrades, plan for any necessary wheel clearance checks and potential suspension adjustments.
Additional considerations when changing size
If you go beyond the factory sizes, keep these factors in mind:
- Changing diameter or width can affect speedometer readings and performance systems.
- Upgrading to larger wheels often requires careful attention to tire profile to keep overall diameter close to the original.
- Mixing sizes front and rear is generally not recommended unless advised by Audi or a tire professional.
Always consult a tire professional before changing sizes to ensure the new configuration maintains safe handling, traction, and acceleration characteristics.
Summary
The 2009 Audi A4 did not use a single tire size across all models. Typical OE sizes include 205/55R16, 235/45R17, and 245/40R18, depending on trim and wheel package. To be sure, verify the exact size on the door jamb sticker or in the owner's manual, and consult a tire professional if you’re planning replacements or upgrades.