OEM wheel and tire fitment specs for the 2018 Audi A4, including bolt pattern (PCD), center bore diameter, thread size, rim diameter, rim width, wheel offset, and backspacing.
Recorded OEM specifications for the 2018 Audi A4, donor years with overlapping ranges, and a calculator to compare a selected wheel. Range overlap is not a guaranteed fit.
Multiple OEM configurations exist for this vehicle. Fitment can vary by trim, brakes, and factory wheel package – confirm your exact setup before buying.
Center-bore records disagree: year-level hub 66.6 mm vs trim range 66.5–66.5 mm. Interchange below does not treat this as an unqualified match.
Thread-only product links are shopping examples, not verified fits. Seat style is not confirmed here. As an Amazon Associate we earn from qualifying purchases.
Donor vehicles with overlapping OEM specs
These are vehicle-year records whose recorded OEM ranges overlap this 2018 Audi A4. Overlap is not a guarantee that a specific wheel will install. Selected-wheel comparison is in the calculator below.
Evaluated 188 donor years. Listed 24 eligible overlaps (not all evaluated years are compatible). Showing all listed.
Wheel geometryOEM width/offset ranges overlap (not a specific wheel)
Center-bore records disagree (target year-level hub 66.6 mm vs trim range 66.5–66.5 mm). Unqualified overlap is not claimed until the conflict is resolved.
Compare a donor vehicle or custom wheel against this 2018 Audi A4. Use Compare in calculator on a donor row above to fill the donor side of this same calculator.
Compare
Compare wheel compatibility between two vehicles
Wheels from (donor vehicle)
Selected Car:
Custom wheel size (optional)
Tip: change values here to simulate custom wheels and immediately see the impact in the comparison below.
Custom tire size (optional)
Installed on (your vehicle)
Selected Car:
2018 Audi A4
Compare Rims
Specification
Wheels from
Installed on
Result (Click it)
Bolt Pattern
The total number of bolt holes and the diameter of the circle they form.
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5x112
Center Bore
The hole in the center of the wheel that fits over the vehicle’s hub.
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66.5 mm
Thread Size
The size and spacing of the threads on the bolts or nuts that hold the wheel in place.
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M14 x 1.5
Rim Diameter
The wheel diameter in inches that determines which tire sizes will fit.
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17"
Rim Width
The distance between the inner edges of the wheel is measured in inches.
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7.0"
Wheel Offset
How far the wheel sits inward or outward relative to the hub mounting surface.
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42 mm
Backspacing
Shows how much space the wheel takes up toward the inside of the vehicle.
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-
Wheel Fasteners
The type of hardware used to secure the wheel to the vehicle.
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-
Compare Tires
Specification
Wheels from
Installed on
Result (Click it)
Section Width
The width of the tire from sidewall to sidewall, measured in millimeters.
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Aspect Ratio
The height of the tire’s sidewall expressed as a percentage of its width.
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Diameter
The wheel diameter for which the tire is designed to fit.
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Tire Pressure
The recommended air pressure for safe and efficient driving.
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Overall Diameter
The total height of the tire and wheel combined affects clearance and speedometer accuracy.
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-
Wheel Fitment Parts for the 2018 Audi A4
Example products matched to recorded thread, hub, or spacer dimensions. They are not verified fits. Confirm seat style, thickness, and clearance before ordering.
As an Amazon Associate we earn from qualifying purchases. Product availability and pricing may change.
tl;dr
Use the calculator to compare any donor wheels to your 2018 Audi A4. Start from your car’s door-jamb tire placard. Match 5x112, 66.6 mm hub, and M14x1.5 bolts. Keep offset changes small and verify brake and fender clearance before driving.
Recommendation
I build fitments by confirming the baseline, then testing changes. Do this in order:
Confirm your OEM wheel and tire size on the driver door placard. Audi offered multiple packages in 2018. The data below shows mixed 17 and 18 inch info. Use your placard as the baseline in the calculator.
Only consider wheels with 5x112 and a center bore of 66.6 mm. Larger bores can use rings. Smaller bores will not fit the hub.
Thread is M14x1.5. Your A4 uses wheel bolts. Match the correct seat type to your wheels. Check an existing bolt to confirm seat profile.
In the calculator, set “Installed on” to your A4 and enter your confirmed OEM size. Then compare the donor wheel or a custom size. Watch tire diameter, inner clearance, and poke.
Keep total tire diameter change small. Many shops target within about 2 percent. Use the speedometer and fender gap outputs for a reality check.
Keep offset near stock to protect scrub radius and bearing loads. If you widen the wheel, adjust offset to maintain inner clearance first.
Do a physical test fit before mounting tires. Spin the wheel to check caliper, knuckle, and liner clearance at full lock and compression.
Impact
Offset: Lower ET pushes the wheel outward. Too low can poke and rub. Higher ET pulls inward and can hit the strut or control arm.
Width: Wider wheels move both inward and outward from the hub face. The calculator shows inner and outer changes separately. Use that to balance clearance.
Tire diameter: Larger diameter fills the arch and reduces clearance. Smaller diameter lowers the car and speeds up the speedometer.
Centering: A 66.6 mm hub makes hub-centric fit easy. Larger-bore wheels need quality rings for smoothness.
Hardware: Spacers require longer M14x1.5 bolts. Only if needed. Torque to OEM spec from the manual.
Risks
Mixed OEM data: 2018 A4 trims vary. Do not assume size from photos or listings. Use your door placard and OEM documentation.
Seat mismatch: Cone-seat bolts in a ball-seat wheel, or vice versa, can loosen. Confirm visually.
Brake clearance: Many aftermarket designs have thicker spokes. Check barrel and spoke-to-caliper clearance during test fit.
Rubbing: Aggressive offset or diameter can hit liners over bumps. Load the suspension when checking.
Vibration: Running lug-centric without rings on a larger bore often causes shake. Use proper hub rings.
TPMS: Some regions use indirect systems, others direct. Follow your owner’s manual for reset or sensor needs.
Next actions
Known OEM fitment data for 2018 Audi A4
Bolt pattern
5x112
Center bore
66.6 mm
Thread size
M14 x 1.5
OEM wheel size
18 x 8.0, ET40, backspacing 5.57 in
OEM tire size
225/50R17 noted. This varies by trim and package.
Because Audi offered multiple wheel packages, confirm your exact OEM size on the vehicle placard and in your owner’s manual. Use those as the baseline in the calculator.
Checklist
Read your door placard for tire size and load index.
Enter your OEM baseline into the calculator, then compare the donor or custom setup.
Match 5x112 and 66.6 mm hub. Plan hub rings if the wheel bore is larger.
Keep tire diameter change minimal. Verify speedometer and clearance in the calculator.
Confirm bolt seat type and length. Replace hardware as needed.
Test fit on the car. Check lock-to-lock and through suspension travel.
Torque wheel bolts to the OEM spec from your manual. Re-torque after 50–100 miles.
Gotchas
Backspacing differs by wheel width. Do not compare backspacing across different widths without the calculator.
Spacers fix inner rub but can cause outer poke. Model both sides.
Some tire models run wider than labeled. Check section width by brand if you are close.
Use the on-page calculator to validate every change before buying. If anything is unclear, cross-check with your owner’s manual and OEM service information.
Methodology and sources
Wheel interchange depends on more than bolt pattern. Where data is available, this site compares recorded OEM values:
Bolt pattern / PCD
Center bore direction (donor wheel bore must not be smaller than the hub)
Wheel diameter, width, and offset against known OEM ranges
A normal wheel spacer does not change bolt pattern. Hub rings cannot enlarge a wheel bore that is smaller than the hub. Brake clearance and tire package fitment still require vehicle-specific checks when not confirmed in the dataset.
