Are my Wheels Audi or aftermarket?
 

https://cimg8.ibsrv.net/gimg/www.aud...6e3deddb2c.jpg

2008 Audi A4 Quattro Cabrio
I bought the car with these 18" wheels and the door says it should have 17" wheels.. I have a bad vibration/shake @ 40mph. The tires are not in the best shape and the rims have seen many curbs. I assume that if they are Audi that I do not need spacers but some aftermarket wheels do.. I removed the front wheels and there were no spacers installed. I just want to get the car driving like it should!
Thanks...

Should have audi logo on inside of wheel

How long have you had the car? Did it always have the vibration?

It is an aftermarket wheel. Bad luck you didn't make a note of the wheel specs when you had it off. Wheels will not necessarily have an Audi logo, but they will have an Audi part number. More importantly, it will also have the wheel specs, including width and offset (ET).

The B7 was fitted with optional 18" wheels, width of 8", offset is ET43.

Wheels look good, suit the car, look like they may be OZ, who also make some OEM wheels for Audi. Including a similar design for the B7, but it is not the same wheel as yours.

Sounds like you need new tyres, so have the wheels looked at when this is done so they can be checked for any damage / out of round, rebalance etc.

The car is new to me and I am slowly finding all the issues. I just removed the spare and took some pictures.
It looks to be Audi ET43. Now the big question....Do I need a spacer?
Thanks.https://cimg5.ibsrv.net/gimg/www.aud...1a8c56af7b.jpg
https://cimg9.ibsrv.net/gimg/www.aud...357aaeec80.jpg
https://cimg0.ibsrv.net/gimg/www.aud...c6b15e4cd4.jpg
https://cimg1.ibsrv.net/gimg/www.aud...f3122ad1ba.jpg

They are the right fitment for your car, and they are OEM. Ronal are probably Audi's largest wheel supplier.

You most certainly don't need a spacer. New tyres and a balance and you should be fine.

Thanks!

No problem, except I'm wrong! I didn't pick up in your description that your car was a cabriolet. Your wheels are off an A4 sedan (or Avant).

They are the wrong offset - the sedan/avant uses an ET43 offset, the cabriolet uses ET32, which is quite a difference. You should use a spacer if you want to keep using these wheels. 10mm or 12mm should be fine (11mm not typically available). You will need new (longer) wheel bolts as a result, as the existing bolts will be too short, and they need to be ball seat bolts to suit the Audi wheel.

I would use one supplier for tyres and spacers and balancing. Otherwise if you have a balance issue (spacers can compound this), they will point the finger at each other.

Sorry for not picking up on the cabriolet earlier.

Do you think I can fit 12mmm (1/2") or should I just find new wheels?
https://cimg3.ibsrv.net/gimg/www.aud...ac7c9ee5c6.jpg
https://cimg6.ibsrv.net/gimg/www.aud...f850813307.jpg
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https://cimg8.ibsrv.net/gimg/www.aud...fd231e7922.jpg
https://cimg9.ibsrv.net/gimg/www.aud...ba15f011dc.jpg

Yes, 10 to 12mm should be fine. You could go less. You could leave it if you are happy with the look, usually steering / handling issues come when you run a smaller offset than OEM, not greater, and it seems you are not touching any suspension components on the inside of the wheel - there is plenty of room within the B7 series.

If you do a Google or similar search on images for Audi B7 A4 cabriolet and look at cars with stock wheels, you will get a sense of where the wheels should be. Have attached a couple of pics from just such a search - most noticeable on the rears, yours are tucked inside a little.

Personally, I would get the wheels checked to ensure they are not bent and there is no obvious corrosion (from salt), mount new tyres and balance it up - should give you a smooth ride, offset won't affect this. Then if all is okay, consider adding spacers as the final stage. As I said, I like those wheels on the B7, so would only change them if they were damaged. Also, have a look in the specific B7 (and B6, very similar) A4 forums, as most forum traffic is in the model specific forums.

https://cimg8.ibsrv.net/gimg/www.aud...1ca406af4d.png
Source: Google search

https://cimg5.ibsrv.net/gimg/www.aud...fa8489a63f.png
Source: Google search

https://cimg8.ibsrv.net/gimg/www.aud...bd17565904.png
Source: Google search

https://cimg9.ibsrv.net/gimg/www.aud...9ea3db5c5e.jpg
Source: Our A4 cab, on 17" winter wheels