2018 Audi RS 5 Wheel Interchange
2018 Audi RS 5 wheel fitment, explained step by step
I’ll walk you through this the same way I do it in the shop. Think of it as building a clear mental model of what fits, then refining it with the on-page calculator until you can order parts with confidence.
1. Starting point
Here is the verified fitment data we have on file for the 2018 Audi RS 5. I use these values as the baseline inside the calculator before I try any changes.
| Bolt pattern | 5x112 |
| Center bore | 66.5 mm |
| Thread size | M14 x 1.5 |
| Wheel diameter | 20 in |
| Wheel width | 9.0 in |
| Offset | ET 26 mm |
| Backspacing | 5.52 in |
| Tire size shown | 265/35 R19 |
You probably noticed the oddity. The wheel diameter listed is 20 inches, while the tire line shows a 19 inch fitment. That usually means the vehicle was offered with different wheel and tire packages. I see this on performance Audis quite often. Treat the wheel specs and the tire size as package dependent rather than a single fixed combo.
Rule of thumb: match your baseline to what is physically on your car first. Then use the calculator to explore changes. The tire label on the driver’s door jamb and your owner’s manual are the quickest OEM sources to confirm your starting tire size and load rating.
2. Small win
Let’s anchor one solid baseline inside the calculator. Here is the simple setup that gets you moving fast:
- Set “Installed on (your vehicle)” to 2018 Audi RS 5.
- Enter the known wheel spec: 20 x 9.0 with ET 26 mm.
- If your car has 20 inch wheels on it now, enter your current tire size from the door label. If your car is on 19s, switch the rim diameter to 19 and set the tire size to 265/35R19 as a first pass.
As you change rim diameter in the calculator, the tire diameter comparison updates so you can see how speedometer error and fender clearance trend. That immediate visual is the small win. It grounds the conversation in actual numbers rather than guesswork.
Tools that help at this stage:
- Digital caliper to check hub bore and spacer thickness.
- Tire tread depth gauge to verify real-world diameter on worn tires.
3. Expand scope
With a baseline set, I branch out carefully. Think of offset, width, and diameter as a triangle. Push one corner and the others react. Here is how I approach each change:
Width changes
Going wider pushes the inner barrel toward the suspension and the outer lip toward the fender. The calculator’s inner clearance and poke numbers make this easy to visualize. A small width bump, paired with a modest offset tweak, can keep clearances similar to stock.
Offset changes
Lower ET pushes the wheel outward. Higher ET pulls it inward. My rule of thumb is to watch inner clearance first on cars with big brakes and tight upright geometry, like the RS 5. Then check outer poke against fender lips under compression.
Diameter changes
Plus-sizing to a larger wheel typically means a lower-profile tire to keep overall diameter similar. Use the calculator to keep tire diameter within a small percent of your baseline so speedometer impact and gearing change stay reasonable. The calculator’s tire diameter and speed difference readouts make this quick.
Bolt pattern, hub bore, and hardware
The RS 5 hub is 66.5 mm, and the bolt pattern is 5x112 with M14 x 1.5 threads. Aftermarket wheels often have a larger center bore. In that case, hub-centric rings that step down to 66.5 mm help maintain a smooth, vibration-free ride. Match lug or bolt seat style to the wheel and verify hardware length if spacers are involved. If in doubt, confirm seat type and torque with OEM documentation or the wheel manufacturer.
Helpful setup tools:
- Wheel hanger guide pin M14x1.5 for safe mounting on Audi lug-bolt hubs.
- 1/2 inch drive torque wrench to tighten fasteners to the spec in your owner’s manual.
4. Refine
This is where I get precise and reduce surprises.
- Confirm your exact OEM package. The door label lists factory tire sizes. Your owner’s manual and dealer can confirm option-package wheel sizes for your VIN.
- Match tire load index and speed rating to OEM or better. High-performance chassis like the RS 5 feel right when load and construction match the car’s intent.
- Use the calculator to keep inner clearance equal to or greater than your baseline. That helps with upright, spring perch, and brake line clearance.
- Keep outer poke within a visually acceptable range for your fenders. Think of the calculator’s poke number as a preview of stance.
- If using spacers, re-check thread engagement. For M14 hardware, ensure adequate full turns of engagement. Verify with OEM guidance if you are unsure.
If a value is unclear or varies by trim, leave it blank until you verify it against the door label or OEM documentation, then plug it into the calculator to see the downstream effects.
5. Validate
I treat the calculator as the planning tool, then I confirm with a real-world test fit before committing tires.
- Dry fit the wheel on the front and rear hubs without a tire. Spin it to check brake caliper clearance.
- Install one complete wheel and tire. Do a lock-to-lock steering check at stock ride height.
- Bounce the suspension or use a ramp to simulate compression and check the fender lip and liner.
- Torque the hardware to the value specified in your owner’s manual. Re-torque after a short mileage interval as a good practice.
- If vibration appears, confirm hub-centric seating and ring fit to 66.5 mm, then re-check wheel balance.
When numbers and test fit agree, you are set. If they disagree, adjust the offset or width in the calculator a small amount and retest. Small moves tend to solve most issues cleanly.
6. Summary
Quick recap. The 2018 Audi RS 5 takes a 5x112 bolt pattern, 66.5 mm hub bore, and M14 x 1.5 hardware. Our dataset lists a 20 x 9.0 ET 26 wheel with 5.52 inches of backspacing, alongside a 265/35R19 tire size that likely reflects a different factory package. Use your door label to confirm your starting size, set that baseline in the calculator, then explore width, offset, and diameter changes while watching inner clearance, outer poke, and tire diameter.
The mental model is simple. Start from what is on the car, make one change at a time in the calculator, and validate with a careful test fit. That progression keeps performance high and surprises low, and it gives you the confidence to pick wheels and tires that look right and work right.
If you need a couple of helpful tools to support the process, here are the quick links again:
- Digital caliper
- Tire tread depth gauge
- Wheel hanger guide pin M14x1.5 <
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