C5 (Early Model 2000) A6 2.7T Aftermarket Rims
 

Stock rims were 16x7 ET45 Speedlines
225/55/16 (I believe) tires

Just purchased 18x8 ET35 aftermarket w/ 5mm spacers for the front wheels
245/40/18 (100%) tires

Has anyone implemented a similar set up? Any rubbing problems, rims stick out too far etc?

Oh and...
 

Lucas Calipers (4 pad) on the front wheels

Conclusion!
 

Answered my own question.... thanks a lot!

WHEN changing rim width from 7" to 8", (ET45 for the 7") one must (in nearly all cases) make the 8" rim ET45.

BUT the largest deciding factor with our huge brake calipers and aftermarket rims mixed together is.... THE DESIGN OF THE RIM SPOKES

I.E. the new rims I bought were designed like a fan blade, the highest point from the caliper 10mm away and the lowest 3mm away. If the design of the rim was flat and not like a fan blade, it theoretically would have 10mm clearance all the way around. CHECK YOUR RIMS OUT!!!! PUT THE RIM ON AND SPIN BEFORE HAVING TIRES MOUNTED!

Going from 16" to 18" merely increased the mass of the wheel assembly (not good), increased harshness, (not good), all things being equal, actually reduced traction and braking ability (not good), significantly increased the cost of tires (not good), looks cool to many (beauty is in the eyes of the beholder. However this trend to larger and larger wheels is a trend that appears to be without end. Cool overcomes practical. Just my opinion based on all of the test reports that I have read and my own experience.

Why thank you....
 

Honestly internet being, your response was not needed. People like you are the reason I sometimes cringe at the thought of asking any Forum anything.

It doesn't seem to me that you have gone from 16" to 18" rims, with my model of car (C5 A6 2.7T) or know about what I asked; clearance, rubbing or fitment issues due to the large brake calipers. I did not ask your opinion on the obvious factors of changing what a team of engineers at Audi designed 13 years ago.

You just wanted to let me know how stupid my doing so was to your superior Audi knowledge. You are a lame and I'm done ever using this Forum. It seems as if Audi World is full of more people looking to help and answer than those whom would rather have a pissing competition of car knowledge.

Piss away brother I'm on to the next.

Calm down. You have drawn an extreme conclusion from my comments that were not intended. If you like the look of larger wheels (a position that is very popular) so be it. I don't think you are dumb for holding that opinion.

But my posting was not opinion but objective fact. Larger wheels have significantly more mass and contribute to a harsher ride, a loss in performance and higher cost, all things being equal. In my opinion 16" wheels are the sweet spot for many if not most production vehicles. Sorry if my posting hit you the wrong way. In addition the increased mass suggests that the OEM shocks are no longer appropriate for the new application.