QUOTE (ttshark @ Oct 27 2009, 10:30 PM)

I will be running as low a tire size as possible. I'm talking stretched sexiness.
Assuming you are keeping approximately the same overall diameter as stock (a very good idea for speedo accuracy and ABS functionality), the smallest tire recommended on an 18"x9.5" rim is 235/40R18. This will definitely be stretched. With that tire size, your setup will be about 1.25" closer to the fender than stock. Wider tires will make the problem even worse. Rolling the fenders will probably gain you 0.5" to 1.0". I think you are looking at cutting and pulling the fenders to make these rims work.
QUOTE (ttshark @ Oct 27 2009, 10:30 PM)

I am not entirely sure what you mean by hub bore. Can you explain a little further?
The Mazda 6 (like many other cars), has hub-centric rim mounting. There is a raised lip on the hub surface with an outer diameter of 67.1mm that the center hole of the rim fits over. If your aftermarket rims' bore is too small, they won't fit. Too big, and you can get adapters to make up the difference.
QUOTE (ttshark @ Oct 28 2009, 01:40 AM)

Another two questions. Being full alloy, are these Rota wheels considered "light weight" compared to others?
Cast alloy rims are lighter than steel, but not "lightweight" as far as aftermarket rims go. If less weight is your goal, look at forged rims (but be prepared to shell out some money).
QUOTE (ttshark @ Oct 28 2009, 01:40 AM)

And finally, if I run on 17x9.5 instead... (if that exists) would this drastically reduce the chance of rubbing?
The rim diameter and offset are separate specs. Using a smaller rim would dictate a taller tire, but doesn't change the fender clearance. More offset moves the wheel (and tire) away from the fender-- but then you have to make sure to clear the suspension components on the inside.
In fact, the 17" rim actually makes the problem even worse. The 235/45R17 and 245/45R17 sizes aren't recommend for 9.5" rims, so you'd either need to go wider with 255/45R17 or step up to 265/40R17. Now your fender clearance problems would become outrageous without significant re-work of the fenders.
QUOTE (Egierda @ Oct 28 2009, 01:28 AM)

Even at stock ride height, if the suspension gets compressed enough, yes..you'll rub heavily. I guarantee it.
Thank you, thank you, thank you for not repeating the myth!
So many people erroneously think that lowering the suspension causes rubbing issues and raising it fixes them. Lowering the car only makes existing clearance issues show up more easily.