So I finally saved my cash up to purchase some wheels and seeing as this is my first time I had a few questions. I have the x and wanted to run a staggered setup. Was going to most likely go with 20x8.5 and 20x10 in the rear. I'm not lowered yet and really iffy on doing that right now as I live in chicago where the streets are all ****ty and I tend to not slow down over potholes or driveways. (Not a huge fan of the brake pedal, usually just let the car downshift to a stop)

I've read that 245/30/20 and 275/30/20 would be the tire size I should go with so as to not disrupt the awd. Is that correct???

Also offsets really confuse the crap out of me for some reason. I want to get the wheels as close to the fender as possible and I have plans for a akebono brake kit or brembo if the guy I know can ever get a g37 in to make brackets for it (shout out to anyone in GA that would be willing to drive and help out with that one). The wheels im choosing is the niche surge which are concave. I want to go with the look of almost no concave in front and deep concave in the back. What type of offsets am I suppose to run???

 

The absolute best tire sizes for AWD compatibility are~
19" setup~ 235/40/19 & 275/35/19 (rear 0.67% larger) ***
245/40/19 & 275/35/19 (rear 0.52% smaller)
245/40/19 & 285/35/19 (rear 0.51% larger) ***

20" setup~ 235/35/20 & 275/30/20 (rear 0.07% larger) ***
245/35/20 & 285/30/20 (rear 0.07% smaller) ***
245/35/20 & 295/30/20 (rear 0.80 % larger)
245/35/20 & 275/30/20 (rear 0.97% smaller)

Having the rear slightly larger than the front is preferred since the rears wear faster, this will result in a better F to R variance over time.
The sets with *** are the best possible combos.

The tires you listed would result in a 2.67% variance, way over the 1% variance that has been shown to cause issues w/ the AWD, actually you really want to be virtually zero variance to have that much more room for future tread wear, a low tire, etc.

If you don't plan on a drop I'd go w/ 19s, they look better at stock height. If you eventually drop the G than the 20s will look fine.
Need to know if you have a coupe or sedan as far as offsets. Also, here's a template for brake clearance, you can send this to the vendor for them to verify (hopefully they will)
http://infinitig37.com/tech-images/akebonotemplate.pdf

 

Thanks for the info and I have a sedan as far as offsets go

Also is it possible to have a slightly taller sidewall to fill up the gap incase I don't do a drop on 20s??

 

In your first example, you went with a wider tire, but didn't adjust your height radio to adjust. Notice how in each of blnewt's examples, the rear tire has a smaller height radio? The total height ends up being larger for most of the rears since the width is larger. The height ratio is just that, a radio of height to width. It's not an absolute measurement of the tire's height.

Regarding your question about a taller tire all around...I'm sure it's possible, but don't know. At the very least, your speedometer would be off.

 

So the wheels I wanted to go with have a offset of 34 in the front and 40 in the rear. How will that work with a sedan??

 

If those are 20x8.5 and 20x10 those will work OK but I'd go w/ the narrowest tires that I listed, the 235/35/20 & 275/30/20 setup.