mtnxtreme

Looking to buy a set of used Rotor wheels to put on my 18 A5, will any Audi Rotors fit from any model, 18-20 inch ?

SMac770

wheel dimensions specs:
diameter
width
offset

The stock dimensions for a B9 A5 is 18x8.5 et29, 19x8.5 et32, and 20x9 et34. If the wheel of interest is different, then you have to sort if that difference is an issue or not. The A5 brakes (338x30 fixed front, 330x22 floating rear) will fit 17" or larger.

wheel hub specs:
center bore diameter - 66.5
lug bolt pattern - 5x112
lug bolt seat - R13

If they are 8K..., 8T..., 8W..., 4G..., 4H..., 4K..., 4N... wheel p/ns, they are the appropriate wheel hub specs. The Q5 (8R..., 80...) and Mk2 Q7 (4M...) wheels are R14 lug seat, but otherwise the same. The B9 cars are the lowest kg load, so all the wheels are sufficient load spec.

mtnxtreme

The wheels I’m looking at are 19 inch off of a 2020 Audi RS3

mtnxtreme

This is the wheels I’m looking at :


2.5TFSI
394 hp
Generation: 8V Facelift [2017 .. 2020]
Production: [2019 .. 2020]
Sales regions: USA+, Canada
Power: 394 hp | 294 kW | 400 PS
Engine: 2.5 L, DNWA, I5 , Petrol
Center Bore / Hub Bore: 57.1 mm
Bolt Pattern (PCD): 5x112
Wheel Fasteners: Lug bolts
Thread Size: M14 x 1.5
Wheel Tightening Torque: unknown
TIRE

RIM

OFFSET RANGE
mm
Tire Pressure (front / rear)
bar
OE 235/35ZR19 91Y 8Jx19 ET42 40 - 44 2.7
OE 235/35ZR19 91Y 8Jx19 ET49 47 - 51 2.7
255/30ZR19 91Y front axle
235/35ZR19 91Y rear axle 8.5Jx19 ET46
8Jx19 ET42 44 - 48
40 - 44
2.7
255/30ZR19 91Y front axle
235/35ZR19 91Y rear axle 8.5Jx19 ET53
8Jx19 ET49 51 - 55
47 - 51
2.7

SMac770

A3/TT/Q3 are still on the old VW 57.1 center bore. And the wheels tend to be very high offset. It could work out since you'd need a spacer anyway, but you'd need one that fits over a 66.5 hub and into a 57.1 wheel.

Also, the 8V RS3 19" rotors are in a variety of sizes, as it offered square and staggered (wide front, skinny rear) options. You'd want same width and offset all around on an A4/A5.
4x 19x8.0 et42
4x 19x8.0 et49
2x 19x8.5 et46 front / 2x 19x8.0 et42 rear
2x 19x8.5 et53 front / 2x 19x8.0 et49 rear
Don't know what makes the call on using the et42 wheels vs the et49 wheels.

So take the 19x8.5 et46, you'd need 14mm spacers to bring that back to stock A5 et32. The A5 18" are on a skinner tire (245 vs 255), which is probably why it runs the lower et of 29 to keep that same outer tire face placement. So 14mm spacers to et32 if you ran 255, or 17mm spacers to et29 if you ran 245.

mtnxtreme

The seller said they are about ET50 and should make them out further but pretty flush with wheel well ? And can have the centers drilled to the correct center bore ?

SMac770

"about et50"? If they are Audi OE wheels, the etxx is marked on the inside of the wheel, as well as the full p/n itself. There should be no guessing as to what you're buying.

"should make them out further but pretty flush with wheel well"? I don't know what you're trying to say there. I more positive offset value moves the outer face of the wheel towards the mounting face (where it mounts to the wheel hub). Think of et53 having a very flat look and et32 having a deeper look. Ie, the opposite of what most people are trying to do; an increase in offset will "pull the wheels inward". Adding a spacer is effectively reducing the offset. et32, 8mm spacer, effective offset of 32-8=24.

https://www.wheel-size.com/calc/ Play with that if you don't understand offset.

You're going to need a large spacer with those wheels, so I'd just get a spacer that manages the center bore change, before I spent money drilling. There's nothing special about those wheels to really justify all the hacking to make them feasible for this application, imo.