The new Audi RS5 B10 might be one of the best looking cars Audi has ever built. Wide rear quarters, a properly resolved arch line, and the RS6-style five Y spoke wheels as standard. And yet, from the factory, it doesn't quite sit right. There's a visible arch gap, the wheels tuck too far into the body, and a car this wide deserves better.

The quickest fix is a set of wheel spacers. We've just taken delivery of our own RS5 Avant, and before it goes anywhere near the rest of the build, we tested 10mm, 12.5mm, 15mm and 20mm spacers on the factory wheels to find the ideal fitment. This is what we found.

What Is Stance, and Why Does It Matter?

Stance is how a car sits. The relationship between the wheel, the tyre and the arch. Ride height, arch gap, and how flush the wheel face sits against the bodywork. Get it right and the car looks planted, intentional, finished. Get it wrong and even a 640 horsepower estate can look like it's wearing someone else's shoes.

Modern performance cars almost always arrive with conservative fitment. Manufacturers have to account for snow chains, full loads and worldwide homologation, so the wheels sit inboard and the arches look under-filled. The B10 RS5 is no exception.

There are three ways to improve it:

Lowering the car. Springs or coilovers reduce the vertical arch gap and drop the centre of gravity. The biggest visual change, but also the most involved.

Wider aftermarket wheels. A new set with the correct width and offset fills the arch properly and transforms the car. The most complete solution, and the most expensive.

Wheel spacers. Spacers push the factory wheels outward to sit flush with the arch. They're the most cost-effective change you can make, and the right choice if you want to keep the OEM wheels. On the B10 RS5, that's a genuinely tempting option, because the standard five Y spoke design is one of the best factory wheels Audi currently fits to anything.

How Do Wheel Spacers Work?

A wheel spacer is a precision-machined aluminium disc that sits between the hub and the wheel, moving the wheel outward by its stated thickness. Quality hubcentric spacers replicate the hub's locating ring on their outer face, so the wheel remains centred on the spacer exactly as it would on the hub itself. Longer wheel bolts are supplied to maintain the correct thread engagement.

B10 RS5 hub specification

The B10 platform carries over the familiar Audi fitment: a 5x112 bolt pattern with a 66.5mm centre bore and M14x1.5 ball seat bolts. Any spacer for this car must be hubcentric to that 66.5mm bore, with the correct ball seat hardware. Conical seat bolts from other platforms will not seat correctly and should never be used.

Frequently asked questions

Are wheel spacers safe? Yes, when they're hubcentric, properly torqued and paired with the correct length bolts. The wheel loads through the hub face exactly as it does from the factory. Cheap universal spacers without hubcentric rings are where problems start, so buy properly.

Are they expensive? No. A quality set of spacers and bolts is a fraction of the cost of new wheels, which is precisely their appeal.

Do they last? Hard-anodised aluminium spacers are effectively a fit-and-forget component. They'll outlast the tyres many times over.

Do they need maintenance? Only what your wheels already get. Re-torque the bolts after the first 50 to 100 miles, then check them at routine wheel-off intervals such as tyre changes.

Are they covered under warranty? Spacers themselves carry the supplier's warranty. As for the car, a dealer cannot reject an unrelated warranty claim simply because spacers are fitted, though anything they can plausibly attribute to the modification may be scrutinised. Worth knowing before you commit, as with any modification.

Testing Every Size on the B10 RS5

All testing was carried out on the factory 20-inch five Y spoke wheels with the standard Bridgestone tyres. One thing worth noting early: those Bridgestones carry a pronounced kerb protector rib, which visually pushes the tyre closer to the arch than the wheel face actually sits.

10mm

The subtle option. With the thick kerb protector on the factory Bridgestones, 10mm already looks close to flush. For anyone wanting a gentle improvement without changing the car's character, this works. For us, it left a little on the table.

12.5mm

This is the one. The wheel face sits level with the arch, the kerb protector fills the last of the gap, and the car finally looks as wide as it actually is. Our gauge is simple: looking at the arch straight on, you shouldn't really see the top of the tyre. At 12.5mm, only the bottom of the Bridgestone logo remains visible. Bang on.

15mm

Two and a half millimetres further and it tips over the edge. There's too much tyre on show, and the wheel starts to feel like it's escaping the arch rather than filling it. If you're running a different tyre with a slimmer kerb protector, 15mm could work. On the factory Bridgestones, it's a step too far.

20mm

For the crazy ones. At 20mm, the RS5 starts to look like a 4x4. We fitted them so you don't have to. That said, some people like their wheels poking, and if that's you, they're available.

Our Recommended Setup

12.5mm hubcentric spacers, front and rear, on the factory 20-inch five Y spoke wheels.

One critical point: the RS5's quattro system requires a square setup. Whatever spacer size you run at the front, run the same at the rear. Don't stagger spacer sizes on this car.

If your car is a Vorsprung or Carbon edition on the optional 21-inch wheels, the offsets differ slightly and the ideal size may shift. We'll cover those in a separate fitment guide.

We'd also strongly recommend adding locking wheel bolts when ordering. These are expensive wheels on a desirable car, and the standard bolts offer no protection.

The spacers are the first step in what's going to become a much bigger build. Splitter, exhaust and plenty more are already in development for the B10 RS5 and RS5 Avant. If you own one, sign up on the product page and you'll be the first to know when they land.