1. your sizes are far too narrow for any meaningful traction
2. check your tire pressure and alignment specs

 

Well everytire i've run a nonstaggered setup (front and rear the same height ) the car does exactly what you say. Bump up to a 245/45 rear if you want to keep the streched look and your problems will magically go away.

 

Most of that "body roll" is due to the fact that your thread blocks are a lot taller than they were on your old tires, so they bend more. This is why old tires are a lot more responsive than new ones.

You also have the silicone from the moulding process compounding the effect.

Wait 500 miles for the silicone to go away, and you can really lean on the tires. That initial body roll will eventually disappear.

 

i guess i will never understand why people whine and cry about handling problems when they do not use the proper sized tires for the wheel size. but hey, it looks good right? looks are more important that proper handling it seems

 

here is mr z04 again.... lol...

it shouldnt be tire size since... many of us use the same specs and even push our cars to the limits. My car feels solid and actually can take turns easier than if i had humoungous rear tires. It is much more responsive.

I agree with the other 2, has to be the tires. They must have sidewalls that are too stiff or too soft for your preference? Are you the only one with 245/40/18 all around in your area? if you were close to me... id let you try mine, it feels so good.

 

There are better tire choices available:

https://my350z.com/forum/wheels-tire...uld-i-get.html

EDIT: You put a 245 mm tire on a 9.5 inch wheel. Please don’t complain. It makes you look silly.

 

check and see if your tires are mounted correctly. I believe they are 1 directional.

 

Check your tire pressure all around. Always start with the simplest of things.

 

Read post #22, explains a lot. Well more about it, when you lower just the rear of your car (yes you did with your tire size) you change the front, increasing the castor. By doing this the car become more responsive (twitchy) especially on grooved and uneven streets. Some people have no problems with this, some of us do this setup for the track. I know personally with Vegas roads i would not want to daily drive on a set up like that.

Its not just VCD/TCS that is setup for staggered height, your suspension is too.

 

Its not just VCD/TCS that is setup for staggered height, you suspension is too.

What i was figuring was that if i can get some good sway bars i can adjust come of the difference of the suspension setups that stock has. Obviously th car is setup for a staggered setup but i am running a non stagger setup to eliminate the nasty understeer that the car has, so my main question is if i can a good set of sways could I tune it to run this setup better and eliminate this "body roll" feeling? if so how should i set up the sways?

 

You can get front control arms with Caster adjustment or like you said you want a non stagger for understeer reasons, buy 245/45's for the rear. Sways will do nothing for what you indicate.

 

i know new tires always come with a thin coating of protective "gel like material" and fades away after 100 miles or so? this could be an added factor. heard nothing but bad reviews about the 555

 

245/40/18 is way too small for that 9.5" width. I know there's that silicone layer on new tires that make it feel "slippery", but, the tire size doesn't help either. You should be up like 265/35 or something. Too Stiff or too soft sidewalls has nothing to do with it.

 

Nitto 555 FTL