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AUDI B8 & B9 (A4/S4/A5/S5) FITMENT
The Audi B8 (2009–2016) and B9 (2017+) platforms are the backbone of the European sport sedan/coupe segment. The S4's supercharged 3.0T V6 (B8) produces 333 hp, while the B9 S4 moved to a turbocharged 3.0T with 349 hp. The S5 coupe variants share identical specs. All use a 5x112 bolt pattern with a 66.6mm center bore. The Quattro AWD system demands square setups to protect the center differential. These cars respond beautifully to lightweight forged wheels — the combination of AWD weight (3,800–4,000 lbs) and sport sedan handling makes unsprung weight reduction immediately noticeable.
Quick Reference
Bolt Pattern: 5x112 | Center Bore: 66.6mm | Hub Type: Ball Seat | Lug Torque: 120 Nm (89 ft-lb)
Quattro AWD: Always run square setups to protect the center differential. Staggered setups can cause premature differential wear and ABS/traction control errors.
19" Square — Street Standard
19 inches fills the B8/B9's clean fender lines aggressively and provides the visual presence that matches the S-line's performance credentials.
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19" Flush Square
The enthusiast standard for the B8/B9 platform — aggressive without modifications.
- Recommended Size: 19x9.5 ET35 all around
- Street Tires: 255/35R19 Square
- Performance Tires: 265/30R19 Square
- B9 RS5 Note: The RS5 has wider fenders and accommodates ET30 for a more aggressive stance.
Why this setup: ET35 positions the 9.5" wheel flush with the B8/B9's fender line — the car looks transformed compared to the factory 18" wheels with high offsets. The 255mm tire provides excellent grip for the S4/S5's 333–349 hp through all four corners. On a 3,900 lb AWD car, forged wheels saving 4–5 lbs per corner create a noticeable improvement in steering precision and braking feel. The S4/S5 with sport suspension sits lower than the A4/A5 — confirm ET35 clearance at full compression on lowered S-models.
18" Square — Track & Comfort
18 inches provides better tire selection, improved ride quality, and reduced unsprung weight for both track use and daily comfort.
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18" Lightweight Track Square
Better tire selection and ride quality for spirited driving and track days.
- Recommended Size: 18x9 ET38 all around
- Track Tires (200TW): 255/40R18 Square
- R-Compound: 265/35R18 Square
Why this setup: 18-inch wheels clear all factory brake configurations including the S4/S5 brakes. The taller 40-series sidewall provides better ride comfort for daily driving and better curb compliance for track use. The 255mm tire at 18" provides enormous grip for a car this heavy — the Quattro system distributes the power so effectively that the tires are rarely overwhelmed. A forged 18x9 at ~19 lbs is a significant upgrade over the factory 25+ lb cast options.
Recommended Tires by Use Case
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Audi B8/B9 Tire Selection Guide
- Street Performance: Michelin Pilot Sport 4S (255/35R19) — the benchmark for sport sedans. Outstanding wet and dry grip with low noise.
- All-Season: Continental ExtremeContact DWS 06 Plus (255/35R19) — the default for daily-driven Quattro cars. Strong dry grip with genuine cold-weather capability.
- Track Day (200TW): Yokohama Advan A052 (255/40R18) — highest peak grip. The S4 on A052s exploits the Quattro system's full potential.
- Grand Touring: Pirelli P-Zero PZ4 — Audi OEM approved. Refined highway manners with a premium sidewall appearance.
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