18 or 19"

[Staffylover]

We are buying some replica alloy wheels for our A4 SE but are confused as to whether the 18 or 19" would be better, it currently has 17" wheels on.
Hubby wants 19" and personally I don't mind as long as the ride is not affected.
Has anyone done this and what would you recommend?
Thanks

[EssexGonzo]

I've never ridden in an A4 with 19s, but have with 17s and 18s. They're all set up on the firm side but whether it's comfortable enough for you is subjective - so only you can tell if you like it.

Inevitably, less of the squishy tyre sidewall will make the ride firmer on the bigger rims - especially if you're jumping from 17s to 19s - so it's safe to say that there will be SOME difference in the ride. I'd recommend getting a test drive in one with 19s from the dealer and see what you prefer. Many people have 19" rims so they must be fine for some.

It also depends on whether you prioritise aesthetics or ride comfort.

[All-rod]

To add my experience going from 17" with 225x55 tyres to 18" with 235x50 did not seem to change ride comfort (apart from filling arches tiny bit more).
I am pretty sure though if I went to 19" with 225x35 it definitely would have...

[EssexGonzo]

To add my experience going from 17" with 225x55 tyres to 18" with 235x50 did not seem to change ride comfort (apart from filling arches tiny bit more).
I am pretty sure though if I went to 19" with 225x35 it definitely would have...

With that 18" size (235/50x18) you've got a very similar height of sidewall to the 17" wheel so I'd expect the ride to be virtually the same. Is the overall diameter of the wheel and tyre not a little too tall with that size?

The standard 18" size for the C6 was 245/40 x 18 which takes the whole inch out of the sidewall and gives it to the metal rim. I think what you've done is maintained sidewall height and increased your overall gearing on the car. (But I'm not an expert.....).

Tyre size calculator here..... Tyre Size Calculator (http://tire-size-conversion.com/tyre-size-calculator/)

[All-rod]

Yes wheels are approx 12mm bigger in diameter overall, but no side effects so far and tbh wheels fit nicer on the car.

[Staffylover]

I've opted for the 18"

[Splash]

With that 18" size (235/50x18) you've got a very similar height of sidewall to the 17" wheel so I'd expect the ride to be virtually the same. Is the overall diameter of the wheel and tyre not a little too tall with that size?

The standard 18" size for the C6 was 245/40 x 18 which takes the whole inch out of the sidewall and gives it to the metal rim. I think what you've done is maintained sidewall height and increased your overall gearing on the car. (But I'm not an expert.....).

Tyre size calculator here..... Tyre Size Calculator (http://tire-size-conversion.com/tyre-size-calculator/)
For C6 allroad its actually 45 profile, so 245/45 R 18. I use that size in an off-road pattern for 3/4 of the year but as the pattern is no longer available I was going to swap to the larger diameter 235/50 18 which is virtually interchangeable with my 235/55 17 winters. I've not noticed any adverse ride, but would probably find the original (SpEd) 245/40 R 19s a lot firmer, ignoring the trick allroad suspension.

Assuming its a B7 A4 (like I had), 19" would require 35 profile for same/similar tyre width. That might be a bit harsh, and potential prone to damage unless Staffylover went 245 width to provide some more protection.
I don't know the B8 permutations, either official or by acceptable conversion.