Will this work? 7.5”x17”to 8.5”x18

[D1sc]

I picked up a set of wheels from a 05 A8 and I want to try to put them on my A3. I measured the same 6.5”on the back of both wheels. Does seem to be multiple other problems.

 

[KneeGrinder]

Ideal tire section width for 7.5 is 215/225. 8.5 is 235/245. Might be an issue.

 

[D1sc]

Me too. Maybe a good setup of coil overs and shocks could help. It kinda looks like it is too wide,It would be nice to get an old tire mounted on it.(L front with 18 bolted on.)

 

[930.engineering]

.
width - as mentioned you should run a 235/40 R18 tire for 8.5" wheel
bore - is it the same 57.1 mm as your A3 8P? (some later Audi use 66.5 mm)
offset - A3 8P/8PA use highish ET54, I'd guess the A8 use ET43/44 (like A6 4F) or even lower . . . .
.

 

[CapriRacer]

I would use Tire Rack and look at the differences between the 2 vehicles. That will also help in tire sizing!

 

[D1sc]

I did look at data from a couple sources before I got them.

 

[ET16]

https://www.willtheyfit.com/