About This Audi S4 B9 Build
We love featuring real builds from real owners. This Blue Audi S4 B9 sits on a set of 19×9.5-inch BC Forged RS31 wheels, and the result speaks for itself.
The owner chose BC Forged for a reason. This brand delivers serious quality and a design language that turns heads at every car meet. We see hundreds of Audi S4 builds come through WheelFront every month, but this one stands out. The combination of the Blue exterior with the BC Forged RS31 creates a look that balances aggression with elegance.
Fitment Breakdown: BC Forged RS31 on the Audi S4 B9
I walked around this B9 S4 for twenty minutes just to admire the stance. The 19x9.5 BC Forged RS31 setup hits the sweet spot for this chassis. We see a lot of aggressive setups, but this specific width fills the wheel wells perfectly without looking like a track-day disaster.
The offset here matters more than anything else. By pushing the wheels out just enough, the RS31s sit flush with the fenders. You get that planted look without needing to pull the metal or butcher the arch liners.
BC Forged nailed the hub bore tolerance on these wheels. They slide onto the Audi hubs like they came from the factory line. We checked the caliper clearance and found plenty of room for those beefy S4 stoppers. You will not deal with any annoying wheel spacer headaches here.
The ABT HAS kit lowers the car just enough to tighten up that wheel gap. It keeps the suspension geometry happy while dropping the center of gravity. When the car compresses through a corner, the tires tuck just inside the fender lips.
Watch out for rubbing if you go too wide on the tires. This build uses a smart tire profile that prevents contact with the inner fender liner. If you push the rubber any wider, you might hear a nasty scrape on big highway dips.
The RS31 spoke design creates a nice sense of depth. Even with a 19-inch diameter, the barrel design makes the wheel look bigger than it actually is. It balances the visual weight of the S4 perfectly.
What We Recommend for Audi S4 B9 Owners
If you want this look, stick to the 19-inch diameter. It gives you the best balance between ride comfort and aggressive handling. We have tested 20s, but they often ruin the ride quality on these daily-driven sedans.
For offsets, aim for the mid-30s to low-40s range. Anything lower will poke too much and ruin the lines of the car. We have seen owners try to force aggressive offsets, and they always end up with smashed fender paint.
Keep your setup square for better tire rotation and predictable handling. Staggered setups on these Quattro systems are a recipe for trouble with the center differential. Stick to the same width and offset on all four corners to keep the car happy.
Do not go overboard with tire stretch. You need a sidewall that offers some protection against potholes. A slightly wider tire helps fill the arch and gives you a chunkier, more aggressive aesthetic that matches the S4 personality.
Avoid cheap spacers if you can help it. Buying custom-offset wheels like these BC Forged units ensures a hub-centric fitment. It keeps the vibration out of your steering wheel at high speeds.
Style and Build Analysis
The Brushed Clear finish is a masterstroke against that deep Blue paint. It creates a high-contrast look that pops under the sun. Most people go for black wheels, but this metallic finish catches the light in a much more sophisticated way.
The RS31 is a clean, multi-spoke design that echoes Audi’s own heritage. It looks like a high-end OEM plus upgrade. It feels purposeful and fast rather than flashy or tacky.
When you stand back from the car, the proportions feel just right. The wheels draw your eye immediately without distracting from the body lines. It is a cohesive build that looks fast even when parked.
We compare this to a lot of other builds we see at meets. Most guys overdo it with too much carbon or gaudy colors. This owner chose restraint and quality, and the result speaks for itself.
The road presence is undeniable because of the stance. A car that sits this perfectly on its wheels looks like it belongs on the cover of a magazine. It is the ultimate evolution of the B9 platform.
Why We Love This Build
This Blue S4 looks like a predator waiting to strike. The Brushed Clear RS31s catch the light, reflecting the sky and the pavement in a constant dance. It makes the car look expensive, sharp, and totally dialed in.
We love the way the ABT suspension makes the wheels look like they were carved specifically for these arches. Every time I look at this car, I want to drive it through a mountain pass. It captures the spirit of a true driver’s machine.
You can tell the owner cares about the details. This is not just another car with wheels slapped on; it is a vision executed with precision. Go build something that looks this good.
Full Specs Breakdown
Here is exactly what this owner is running. We break down every detail so you can replicate this build or use it as a starting point for your own setup.
- Car Make & Model: Audi S4 B9
- Vehicle Color: Blue
- Wheel Brand & Model: BC Forged RS31
- Wheel Size: 19×9.5
- Offset: Contact dealer
- Wheel Finish: Brushed Clear
- Suspension: ABT HAS
Before You Buy: Fitment Checklist
We talk to Audi S4 owners every day. These are the questions we hear most before they pull the trigger on new wheels.
Will 19×9.5-inch wheels fit my Audi S4? Yes, but fitment depends on width, offset, and tire size working together. A wrong offset means rubbing. A wrong tire size means poor handling. Always verify all three.
Do I need to modify my fenders? That depends on your offset and suspension. A conservative offset with stock ride height usually fits without modification. Go aggressive and you may need to roll or pull your fenders.
Can I daily-drive this setup? Absolutely. Thousands of Audi S4 owners run 19×9.5-inch wheels every day. The key is choosing the right tire with enough sidewall to absorb road imperfections.
