Here is my car with new Potenza RE760 225/45
R18, Mazdaspeed V6 drop on a 6i hatch.
They rub!!! Last setup was 225/40
R18 so just a bit higher supposed to clear fender. Fail! So forget about 225/50 profiles tire on those wheels.
Back from the shop with all 4 17" oem wheel with oem tires (200lbs), they rub very lightly when turning hard or high waves in the road.
After 4 years, the rear sag makes it a bit too low so I will add those Jegs spacers to give back an inch of gap and even the front/rear drop that never been levelled anyway. Bump stopper was trimmed by 1 step when I installed the MS coils. Maybe I should buy and put back full length bump stoppers. I'll see the effect of spacers first.
I will write a review of those tires within next days but for now:
Thank you very much for the pics. Now I know exactly what I will be dealing with. It makes me wonder if I made the right decision to go with the RX-8 wheels, but I guess it's too late now.
I also see that running a 50 series tire will most definitely be too big.
The MS springs on your car lower it farther than I want to go. Especially in the rear. It looks like RB springs are definitely the way to go for me.
So now I am wondering if I can get away with the 45 series tire with the RB springs and not have rubbing. I guess if I really had to I could sacrifice a little suspension travel and make a longer bump stop for the rear suspension. Of course I really don't want to have to do that.
As stated directly above, a 225/50 tire is considered oversized for our car. If you'd like to maintain sidewall compliance for a softer ride, I would recommend sticking with 17s and/or going to a Koni FSD shock when you upgrade. You should also select a tire with a less rigid sidewall to maintain ride comfort. It's tough for many to find a balance between handling and ride quality since most aftermarket handling improvements will be a result of firming up the OEM suspension/chassis. The addition of sway bars will make your suspension less laterally compliant, which is often perceived as more rigid under daily driving conditions.
For your situation, I would recommend a 225/45/18 tire and either RB or Mazdaspeed springs.
As the car is now, it certainly rides nice but it is too soft and the rear end also wallows like a pregnant water buffalo over bumps in corners.
I want to stiffen it up, but I don't want to go too far. Nicely controlled and damped ride, yet not jarring to the point of causing tire skip over expansion joints or rattling my filling out over potholes.
So yes, it definitely looks like the 45 series tire with the RB springs are the way to go. I don't have the coin for the koni dampers, but I think the Tokico's offered by RB along with a set of RB bars may just be my ticket. Although the RB bars seem to be the largest diameter available. Are there other bars available that are larger than stock yet a little smaller than the RB bars?
I've got one chance to get this right without wasting money so I really really appreciate your time and info. Thank You.