Zach

I can see that wider tires can get a larger contact patch (given wide enough wheels to keep the tires in the proper shape) but was wondering why so many people are interested in 18" wheels. The outside diameter is slightly larger, which probably gives a slightly longer contact patch, but that's got to be a very small effect. Does the 5% shorter sidewall most people are going with make a noticeable difference in handling? The reason I ask is because my primary interest in changing wheels is to save weight, and it looks like it will be significantly more expensive to save the same amount of weight using 18" wheels as I could using 17" wheels. Also, are people switching to wider tires because they really need the traction, or primarily for looks?

JAH

Rough ride, bent wheels, super expensive tires, that's about it.

ErikR

Don't forget heavy and prone to theft.

s4demie

Unless you plan on racing,autocrossing,or doing a lot of track events,the trade-offs mentioned by JAH aren't worth it.18s sure look cool though!

Just a stock S4

I've half wanted to downsize to 16s .. and clearly will for the winter. 17 is borderline impractical and 18s must be a total pain. Unless you don;t mind spending a lot on new wheels or dont drive on normal roads. I'm quite freindly with the not-so-local wheel fixing shop - - - from my 15" wheels on my 90q20v!

Grant

Silver S4

if your watching the road and paying attention instead of wondering how many people might be looking at your car or if the good looking girl next to you is actually interested in you or wondering why your driving your dads car, you pretty much can avoid them.

I am riding 19's prmiarily for the looks, but I have to say that I can probably out corner most of the S4's on this forum for the shear reason that I have no tire roll. Granted I have to be more careful about where I am driving, but that's the trad off for better steering.

Yes they are expensive, they can weigh more and tire are not cheap. But the car cost 40K whats another couple K on wheels.

Warren Wang

If your tires don't roll over at all, like the old BFG R1's (which I used to have a set of), you get crappy wet weather performance, and your car will break away very quickly, with little warning. Wet OR dry. Also, with a larger aspect ratio, you can fine tune the suspension more than you can with a low aspect ratio tire. Plus, it's a hell of a lot cheaper to buy the more common sizes with larger aspect ratios.

You can't corner faster than on a tire that you don't care about. Witness my old Proxes T1+'s on my old A4. I should have taken some pictures of those tires. I was well into the tread wear markers, and it would slide like mad, and the car would roll more than my S4, but oddly, it performed far better in auto-x situations than my S4 has so far. Those tires were nearly bald, crusty, cracked and dry. I loved it.

As for "cornering faster", that's 99% driver, 1% car. Tire roll has very, very little to do with it. As witnessed by a few of us at FATT sessions when a good instructor takes out one of the beater 80's something Caprices and scares the **** out of everyone else on the track. Let's see how you like playing with a 2 ton near junkyard condition barge that, oddly enough, hauls MUCH ***.

Warren

Marshall Penniford

good post warren! so, 225/45/17's or 235/.40's? 8" rim. Trying to decide... or 225-235/40/18 on 8.5

Juice S4

Re: Yo Silver, Where's a Pic of your S4 wit 19s???

Warren Wang

I couldn't find R-compound in this size that I like, so I'm going with 235/40-17 Yoko A032R's. For the street, I'll probably always stick with 225/45-17. It keeps the speedometer and odometer accurate, and I don't really feel the need for bigger stickier tires on the street, since I'll have a second set.

Warren