i want to get advan tc II's

front :: 18x8.5

Rear :: 18x9.5

What would be the perfect tire sizes i should do?

i was thinking doing 275/35/18 for the rear and 245/35/18

i dont want to go super wide because super wide does nothing and is unneccesary for street...and i live in North Jersey and the roads here are not all that good...

 

I'd go with a 40 instead of the 35

 

I would do 40, too, on 18s

 

40's look too big an nasty on 18's

 

my opinion is stay with the 35's or go with some 19's man...They look so much better on the Z.

 

19's add weight thats not needed...i'm gona autocross the thing and turning 19's is not as easy as turning 18's...

but 19's do look nice!

 

you need 40s, or your throwing the over all diameter off, you cant have it all, cant have short sidewall, 18" rims, and keep the same overall diameter to keep gearing correct.

need to choose what you want, either go with a 40series, get 19" rims, or do neither and mess up your gearing.

 

mess up gearing ??? by like .5% which wont make a difference

 

110.25mm stock

96.25mm on the 35series.

all on 18" tires, 18x25.4mm/in=457.2/2 for radius=228.6mm

now add the sidewall and you get

338.85mm

324.85mm

circumfrence=2pi R

83.5in circumfrence vs 80.1in

indicates 96% of its original circumfrance, or 4% smaller. tiny changes compound quickly in mathematics. and circumfrance is what matters for gearing.

if your ok with that, its your car, but be clear on what your doing.

EDIT, to check this for yourself go to http://www.miata.net/garage/tirecalc.html and put the numbers in, it comes out to 4.1% smaller. where a 40series cuts it to .1

 

ares what size tires did you do on ur wheels? and how big are your wheels?

 

18" with 8.5 and 9.5 wide, same 245/40/18 and 275/40/18

check out the look of em here.

https://my350z.com/gallery/albuo81

if you want them to be safe for street use and not get busted up, 40s are what you need. if you want 35series, then 19" and 35 is what you need.

 

Then you definitely don't want 35s!

 

ares ::

I think i will go with 40's after looking at your wheel setup.

hey by the way i like your set up ... looks good