Ohh thanks for that clarification! I just got my info from tireracks website where you can open the specification sheet for a certain tire.

 

Why staggered? I'm no expert on this but consider when accelerating, weight shifts back, but not enough weight in the rear to keep a narrower tire from losing traction. Thus wider tires allow better grip. Otoh, when braking weight shifts forward. On a motorcycle, under hard braking, up to 100% of the weight can be on the front wheel, resulting in a stoppie. Mcy tires are staggered also. On sport bikes, front is typically 120/70/17, rear 190/55/17 (or 190/50/17, the former allows for faster tip in into corners).

What's the goal here again?

 

My goal? I guess I don't really have a "goal", just certain preferences when it's time to buy new tires.

1. Right now, the current tires are a little narrow for my wheels. So when it's time to replace them, I'm going to get slightly wider tires for better fitment and rear traction.
2. Keep tire diameters pretty close to current without going back to stock sizes because I like the little bit of extra tire gearing / performance since the stock 3.7 gears are too long.
3. Keep sidewalls a little smaller than stock.
4. Don't reduce ride height much more than it is now, because with my 0.75" F + R springs drop, plus a reduced tire diameter, I don't want it much lower.
5. Dont make the steering feel too sloppy / sluggish by putting oversized tires up front.
6. Keep F + R diameters close enough so it doesn't look lopsided or unbalanced in some way.

Of course it won't be possible to achieve all of that lol, but I'd like to get close.

Well I just figured since they come staggered from the factory, the car is designed to handle and function better with that type of setup. I don't know otherwise man.

 

Using your calculations based on revolutions per minute, here are the new numbers for diameters:

Stock front: 26.07
Stock rear: 25.87

Current front: 25.54
Current rear: 25.25

FRONT OPTIONS
245/45/18: 25.87
255/40/18: 25.29

REAR OPTIONS
275/40/18: 25.87
275/35/18: 24.73
265/40/18: 25.54

 

For what it's worth, I think the cars drive better with a square setup. It cuts down a lot of the understeer from factory. The stagger really isn't necessary at stock power levels, and if you're having traction issues in the dry you can always go for a stickier compound. Every person I know of that goes to the track with me has gone to a square setup as well.

Steering feel is very much dictated by tire compound/selection as well, and influenced by the tire sidewall type. Some are simply stiffer than others.

245/45R18 and 275/40R18 is a common staggered set up that's OEM height. As you've noticed, there isn't much other option to get sizes in between too small (275/35) and OEM unless you go to a 19inch wheel.

235/45 and 265/40 is also an option that isn't excessive.