2020 Audi S8 Wheel Interchange

2020 Audi S8 Wheel Interchange and Fitment Guide

You want wheels that fit the first time, clear the big brakes, and ride without vibration. The confusion starts when factory specs vary and aftermarket sizes change offset and diameter at the same time. This page walks you from uncertainty to a validated setup using the on-page calculator and a few professional checks.

Goal

Select, compare, and validate wheel and tire sizes that are safe for a 2020 Audi S8 under real-world constraints. You will use the calculator to model changes, then confirm clearances, hardware, and rolling diameter before buying or installing.

Prerequisites

• Your vehicle: 2020 Audi S8 (verify VIN, brake package, and suspension options if applicable).
• Known OEM baseline values below. Some values can vary by market or package, so treat them as a starting assumption and confirm.

Important: The presence of a 19-inch wheel and a 20-inch tire spec indicates multiple factory packages for 2020. Do not assume your car shipped with the 19-inch setup. Read your tire sidewall and check the wheel markings for the exact OEM baseline on your vehicle. Use the calculator to compare your actual baseline to any proposed setup. When in doubt, validate with the owner’s manual, the door jamb tire label, or an Audi parts catalog for your VIN.

Helpful tools:

• 1/2 inch drive torque wrench for wheel hardware: Search on Amazon
• Digital caliper for hub bore checks: Search on Amazon
• M14x1.5 lug bolts (confirm seat type before purchase): Search on Amazon
• M14x1.5 thread chaser/tap and die set for cleanup (if needed): Search on Amazon

Step by step

1) Identify your actual baseline

• Read current tire sidewall (example format: 265/40R20). Enter this as “Installed on (your vehicle)” in the calculator.
• Check the back of a wheel for its stamped size and offset (example: 9Jx20 ET35). If the stamp is unclear, measure width between bead seats, not outer lips.
• Confirm lug bolt seat type by inspecting an OEM bolt. Match seat type exactly on replacements.

2) Enter known OEM values

Set bolt pattern to 5x112 and center bore to 66.5 mm when filtering donor wheels. Keep thread size M14x1.5 in mind for hardware compatibility. If your car has a 20-inch OEM package, use that as the baseline; if it has the 19-inch package, use 19 x 8.0 ET32 as the wheel baseline.

3) Model custom wheels and tires

• In “Custom wheel size,” adjust rim width and offset. The calculator will show inner and outer position changes. Each 1 inch of width adds about 12.7 mm; half goes inward, half outward, before offset changes.
• Offset trade-off: a lower ET pushes the wheel outward (more fender flush, possible poke). A higher ET tucks the wheel inward (more strut and control arm proximity). Keep brake caliper clearance in mind.
• In “Custom tire size,” adjust section width and aspect ratio. The calculator updates overall tire diameter so you can keep the rolling diameter within a recommended 1–2% of your baseline to protect ABS, speedometer accuracy, and AWD behavior.

4) Check hardware and hub fit

• Aftermarket wheels often have a larger center bore. Use hub-centric rings to step down to 66.5 mm. Plastic or aluminum rings both work when sized correctly.
• Confirm bolt length and seat type. Bolts must engage sufficient threads without bottoming in the hub. Do not mix ball and cone seats.

5) Brake and suspension clearance

• Use the calculator’s inner clearance readout to watch strut and upright spacing as width and offset change.
• Visually compare spoke design to your brake calipers. Deep-face designs may reduce caliper clearance even if offset matches.

Validation

• Diameter validation: Keep total tire diameter within about 1–2% of your actual OEM baseline. Use the calculator comparison to confirm the variance.
• Lock-to-lock test: With the car on the ground, turn full left and right, listening and looking for liner or arm contact.
• Compression test: Load the rear seats or hit a known dip at low speed to check for fender contact.
• Road test: Drive at 50–70 mph. There should be no vibration. If vibration appears, verify hub-centric rings and request a road-force balance.
• Retorque: After a short drive cycle, recheck lug bolt torque to the value in your owner’s manual.
• TPMS: Follow the owner’s manual for TPMS reset or relearn. Some systems are indirect and need a reset through the MMI menus.

Troubleshooting

Rubbing at fender or liner

• Constraint: Outer clearance is exceeded. Trade-off options include slightly higher offset, narrower tire, or a shorter aspect ratio to reduce diameter and section width.

Inner interference near strut or upright

• Constraint: Inner clearance is reduced by width gain and higher ET. Consider a small reduction in ET or a narrower wheel. Validate hub engagement remains sufficient if using any spacer. Maintain hub-centricity to 66.5 mm.

Vibration at speed

• Validation: Check for proper hub-centric rings and exact center bore match. Request a road-force balance and inspect for bent wheels.

Wheel bolts bottoming or incorrect seat

• Assumption broke: Bolt length or seat type mismatched. Confirm M14x1.5 thread, correct seat geometry, and adequate thread engagement. Replace hardware as needed.

Speedometer off after size change

• Constraint: Rolling diameter changed. Use the calculator to bring the custom tire size within the recommended variance window, then recalibrate if your vehicle supports it.

Wrap up

For the 2020 Audi S8, start with verified OEM data from your own car, not assumptions. Use the calculator to model width, offset, and tire changes against your baseline, watching inner and outer clearances and overall diameter. Keep the hub bore at 66.5 mm with rings if needed, match M14x1.5 hardware and seat type, and validate with real-world checks before long drives. With these steps, you move from guesswork to confidence and get a clean, vibration-free fit.