Widest tire you can fit
 

Title says it all what's the biggest I can put without changing anything

stock ride height?

with a proper offset rim you can fit 315 in the back

some brands of tire are wider than others though

stock rims? i think they are 8.5 inches so like 255-265's

Ya stock for now probably the highest I would go is 305 thanks for quick reply

Handling problems with the 8.5 rims, AM says 245's are max some say 255 with fit and most shops will put 275's on but that would be not so good.

9" rims would help and then 275's at most. AM site sized 275 on 10" rims.

I figure if I keep my four stock tires intact: P-Zero 245x40x19's I can sell them for more to off-set the cost of a new set-up. Pinch your tires and they will not perform to spec.

I can also see if one was to be in an accident due to a blow-out and you had 275's on a 8.5 rim...you wouldn't do well in court because you ignored the manufactures recommendations.

Anyway...I want to put 275's on a 19x9" rim up front and the 2013 GT/CS is lowered 1".
Has anyone had a problem with rubbing on 275's up front. I know you can't put 10" rims up front and most recommend 10" for 275's but I believe it would work.

i cant see how 275's in front would be a problem

18x9 275 all the way around will fit. Front will rub a bit at full lock.

Rears can go all the way up to 305 provided you have a wide enough rim.

Yes but I have a 2013, gotta have 19" and it's lowered an inch" so 275 on a 19x9"???

I need a square set-up, 275 P-Zero's for winter, and maybe when a grand falls in my lap two matching 19x10" rims with 555's for summer drags.

I don't want to rub (275's up front). I don't want a staggered 255/285 (bad handling, P-Zero biggest 275) and I don't want 255's square (Not much bigger then my 245's).

See my dilemma, I want the perfect All-Season set-up. It's the Northwest, 555 in 40's with rain?

I run 275/40s on 18x9.5" wheels with a +35 offset on all four corners, lowered 1.5", with no rubbing at all, even when driven hard on the track. It's all in the offset I believe.

265's at all 4 corners on a 9" wide rim

My street rears are 28x12x15. You won't fit anything bigger than that without some modification.