My A4 needs a new set of tires, I want to get a wider tire on the rear, I think it looks sick with the wide fenders on the A4. My friend has a C230 Benz with 225/45/17 on the front and 245/40/17 on the rear, and the rear looks nice, noticably wider. Would this setup work fine on my Audi? When I go wider in the rear do I need to make the front set smaller or could I just still use 235/45/17? And finally could I go even wider in the rear with 255/40/17? Or is that pushing it? Thanks for the info.

 

You can go 255/40/17 in the rear with a 225/45/17 up front... that should get you the same rolling diameter. This is very important, as if you have different circumferences front and rear, you'll kill your differential.
Quattro is a mechanical system that basically keeps all 4 wheels spinning at the same speed. If you have smaller front tires than rear, it'll think that the fronts are spinning faster (more revolutions per mile) and therefore must be slipping. It'll then try and send power to the rear... constantly. Bad news!

Anyways, check tirerack.com and pick a tire. Look at the 'specs' and make sure that whatever tire sizes you go with front and rear have the same diameter... and it'll also say the minimum wheel width that can be used. 255's on a 7.5" wheel (stock size) would look like a balloon, and kind of foolish, if you ask me.
I'd either buy some true staggered wheels if you really want the look (like I did!) or just get 235/45/17 all around again...

EDIT: I just checked tirerack... and I'm now going to burst your bubble.
You can't do it... 255 tires need a wheel at least 8.5" wide... and your stockers are 7.5".
Here's the link:
http://www.tirerack.com/tires/Spec.j...es&place=9

If you want to stay with 17's... and you want a more aggressive stance... buy my old wheels 1400 Canadian, and I'm willing to ship if a deal is worked! hahaha
http://forums.vwvortex.com/zerothread?id=3240286

 

Ok well the 255 are out, I figured it would be a bad idea. I have decided to just get a full set of either 245/40/17 or 245/45/17’s. But what is the difference? The 45s will have a little more sidewall right? Which gives a smoother ride for a small sacrifice in handling? They would pretty much be just like stock but a little wider correct? Where as the 40’s will be wider than stock and have less sidewall? BTW my A4 currently has 235/45/17s on it.

 

Yup, you've got it. The 245/45/17 will not only be wider, but since that 2nd number is a ratio, you'll also have a taller sidewall, too. I've seen 245/40/17 tires on your exact wheels (my dad had a strange winter tire setup for a short time) and it looks alright. I don't like bulge... looks alright on old camaros, but not on an A4.

If I were you, I'd just go with stock 235/45/17 again.

 

I never saw your second post, and I just searched for this thread to see if I got any additional replies. Anyway I still have not ordered the tires yet, I have decided which tire I am getting, but I am still torn on the size. It’s either going to be 245/40/17’s or the stock size of 235/45/17. What exactly do you mean by budge? Do they look like they are coming off the rim? Basically I just don’t want to sacrifice handling or ride quality just to have a slightly wider look on the tires, so stock size might be the way to go for now, then maybe when I get new wheels I can have wider tires without it looking weird. Is anyone here running 245/40/17s? Do you have any pics?

 

If its winter tires id get the 245 45 17, just cause the extra side wall can come in handy for the imclimate weather. Jsut my .02

 

They are just for the summer, I have new winter tires mounted on beater rims for the winter.

 

More rubber in the back = more understeer

 

I just ordered a set of 235/45/17 General Exclaim UHP tires, I doubt the 245's would have been that much wider anyway.