Since our cars have staggered tires (larger in the rear) in stock form, going to a square setup reduces your rear tire width, which if anything is a move in the direction of more oversteer, not less. However, keep in mind how gravity and contact-patch interact. In some ways it's not as much a change as you'd think, and in others it's a very big change in the feel of the car. The hardest part for me to get comfortable with on switching was that the rear end was looser under trail-braking, requiring more careful brake modulation and slight steering corrections at times to prevent an oversteer spin under trail-braking. Once I got used to it, I really liked it though. That little bit of extra looseness makes it easier to get the car rotated just right while trailing.

I don't know if there's an official definition. One of the nice benefits you'd be missing out on, though, is the ability to rotate wheels all over without remounting tires (and only needing spare wheels in one size/offset).

If your saying it comes around fast on corner exit under power than just meter the throttle better or you have some setup issue. 370Zs do not oversteer at the limit from the factory, not even close. Though not nearly as badly as 90% of vehicles on the road probably.
If its on corner entry, might need to look at the way your managing weight transfer with the brake and throttle input.
Yep.

Square refers to running the same wheel width front and rear and kind of assumes your running the same diameter. Offset is just the distance from the actual centerline of the rim to the mounting face in millimeters. Running different offsets will likely prevent your from swapping wheels front to rear easily.

*Didn't know you had replied when I wrote this Wstar, oh well lol.

corner exit
 

Hello,

It seems that at mid corner the back travels faster and into a
decreasing radias half circle cicrle(that is what it feels like). Even though the back is not coming loose.
It feels like what you would think a paper diagram of over steer is. When the rear starts to whip around when the corner pushed to hard and you spin out.

Problem being I am taking slight hot corners on the street not the track.
And it is wanting to fall right into that curl of oversteer. I guess I know the feeling of it happeneing but a bit reserved to push the car to an unwanted spin. But most tight hard corners have a different feeling for the front verses the rear. Front holds firm but rear feels like it will flick out deeper in corner. Most cars I have driven before would tend to loose front grip and slide there first. Not have the back end feel like you when you hammer the throttle out of a corner to fishtail the car.

Guess probably my setup(ride height, preload on coils, etc) I am trying to get better. As to why I also asked about going square next year.

Most rear-wheel-drive cars tend to be over-steery, and most drivers prefer them that way. Most front-wheel-drive cars tend to be under-steery. Lately, some newer rear-wheel-drive cars are tuned at the factory for slight understeer in many cases because it's safer for a novice driver (controlling/recovering from understeer is more instinctual without training and practice). Our Z's are in this category: they are a rear-wheel-drive car, but they have some gentle understeer tendencies unless you really stomp it at the wrong time (at which point VDC will probably kick in, slow you down, and make a mess of everything). With VDC off you can still push yourself into oversteer in a low-speed corner with the throttle pretty easy though.

All of those nuances aside though: unless the car's setup is way out of whack, it's really up to the driver to manage the rest. You might want to make setup changes to change the nature of the car and make it feel more natural to you, but the bottom line is it's on you to control the rear end of the car with throttle and steering inputs. It takes a lot of practice. Personally, I wouldn't go after switching to a square wheel setup just to try to address this issue (which it wouldn't do anyways I don't think) - I'd focus on training yourself instead. Learn to predict better, react better, use smooth-but-fast precise inputs to the throttle and steering, etc. If you get good enough at that stuff, any actual setup problem in the car will just be an annoyance, but not a dangerous hinderance.

TL;DR - Sign up for a DE or Auto-X event near you ASAP :p Experimenting with a car you can't control on the street is dangerous.

Brian and I ran 18x12 wheels with 320 width Hoosier slicks square at Laguna Seca. The car felt incredibly balanced. The car didnt oversteer much at all. had a slightest hint of understeer in some turns but not bad.

tech article on going square from long acre racing
 

As a newbie I found this pretty informative.

http://www.longacreracing.com/articl...t/Squaring.pdf

the suspension has to be tuned around a square tire setup to be able to use the grip to on both ends to its potential

That goes way past any kind of tuning or setup I've ever done on my car :) All I mean by "square setup" is the front and rear wheels are identical.

I switched to square(per clint and some companies recommendation) and it does balance the OEM setup a lot better. Knowing a bit more now I can see Clint's point on tuning with a square setup.

With a good corner balance and correct spring rates, for someone that knows what they are doing, a wider track, especially upfront on a car with an engine that stands up tall is an advantage.

Wider track up front helps with our high CG (v6). Without a square wheel base the car is going to inherently always "push". It's basic geometry and physics. Pushing is fixable via sway bars, but if you don't have to deal with a geometry problem, why should you?

Don't want to be negative, but this is exactly why I don't like a lot of the Z Specs in the "racing" world. They aren't good specs for our car.

What are the pluses and minuses of going square vs. staggered? I've ran staggered since I got the car in 2009 and have tweaked everything to the way I like it. But now, I'm going from 19 to 18" wheels and found out that NT05's don't come in 245 45 18 fro the fronts, so I was considering going square, but that would mean I need to change my camber, toe, sway bar settings, etc. to fine tune everything again (which I don't mind doing if there's more advantages to going square).

Originally, I was going to go 18x9 fronts and 18x10 rears on the Forgestar F14's and 245 45 fronts, 275 40 rears, which would keep the overall diameter same as stock. But since NT05's don't come in 45 sidewall for the 245 fronts, I'll need to either go to a 40 sidewall front and 35 sidewall rear, which would decrease the overall diameter by about 1", which I don't want to do b/c I need to drive this car daily also - and even as is, I'm having a hard time on driveways already. 1" lower would really be a pain to drive on the street.

If I ran square, it'd be 275 40 18's all around on 18x10 wheels. What offsets would you recommend if I wanted close to flush front and rear? Or keep the same offset front and rear and use a spacer? In either case, please recommend what offsets and what spacer size I'll need. So hard to decide! Your inputs would help a lot. Thanks.

I run Enkei PF01's, 18x9.5 +35 front, 18x10.5 +15 rear which sits pretty flush with no spacers necessary over the sport brakes. Right now I have Toyo R888 275/40r18 on them which have felt great. After they're done I'm going to try a staggered tire though, Nitto NT01 275/40r18 front 305/35r18 rear. We'll see how it handles then.

Did you start with 19" wheels stock? If so, going down to 18" wheels and staying with the 40 size sidewalls on the tires, did you notice a difference in overall diameter? By the numbers, going from 245 40 19 (front) to 245 40 18 should decrease the overall diameter by about 1", which I'm tyring to avoid.

Did you notice a difference? Should I even worry about that?

Do you happen to have pics of your car on this setup?

Why go through all the expense of switching diameters and your setup if you are running NT05? They are your biggest limitation and nothing you do is going to make you much faster with them.
Now if you are going to the NT01 then that is a whole other discussion.

I have a set of hankook RS3's 275/35r19 on my stock Rays which I do like. I purchased the Enkeis which were 18" and went with a 275/40 to keep the same height because the car is lowered already and a smaller sidewall would make it an additional inch lower and I'd scrape everywhere.

One downside is that it will make your speedo read about 3% high. Possible upside and downside: effectively lowers the gearing on the car slightly.

Would be nice if more track tires were made in 275/40R18. Seems like 285/35R18 is pretty much the only option.

The difference in diameter between a 285/35R18 and a 275/35R19 is only .7" so ride height change should be only about .35"