EvEr_34

Ok i'm resigning to the fact that i am totally useless when it comes to wheels, offsets, diameters etc etc etc. Been searching most of the afternoon in the wheels section and i think i've come out of it more confused than i was. SO PLEASE HELP ME!

I've already decided that i will be going with GT-7 in silver (own a super black so should look good) Also decided that i will be going with 18' rims with a drop. Here lies my question. What would you consider to be the ultimate "look" in regards to tire size?? I would like to go as wide as i can without overdoing it (if you know what i mean) If you could also point out ideal rim sizes. i.e 245 looks better on 9 in rim etc etc.

One last question with that. I see that some of you have gone to let's say 18 x 9 rims in front with 245. I have noticed that sidewalls are now at 40 rather that 45' (stock) why is this?

Thanks for your help

2003z

iTrader: (7)

They go from a 225/45-18 to a 245/40-18 because it is close to the same diameter. You want 245/40 front and 275/40 rear. 245, mine are in 19, but for 245, I went 8" +21 offset and rear 275s with 10" wide, +27 offset. Looks perfect.

shaneotool

He's right. If you go 8 or 9" in front and 9 or 10" in back, these will be perfect.

wheelstudio

I know there are plenty of links and im gonna get flamed for this but what if the links dont work or some of you want this for personal reference:

Lets use the beloved 350z with 18" option as an example

eg: 225/45-18 (front tire size)
225=section width /45=aspect ratio -18 wheel diameter

Section width: is how wide the tire is

Aspect ratio: is a percentage relating to the section width. A 225 tire with a 45 aspect ratio is same as a tires profile or how much sidewall is on the tire has and this is in direct relation to what the section width is, as it is a percentage of the width.

Wheel diameter: this is just exactly what it is. The proper size and only size wheel diameter you may fit these tires to.

now overall diameter is where some people get confused

Overall diameter is the measurement for your overall wheel and tire or how tall your tire is when mounted. Your speedometer, ABS, traction control all are calibrated for these OE sizes that is why it is recommended to stay within these specs or as close as possible. no more than 1" on most passenger cars.
To find a tires overall diameter use the following formula

A- 225/45-18
B- 225x.45=101.25
C- 101.25x2=202.5
D- 202.5/25.4=7.97
E- 7.97+18=25.97

A-Tire size

B- Multiply the section width by the aspect ratio (remember to put the decimal point as the aspect ratio is a percentage)

C- Multiply by 2

D- divide by 25.4 to convert from metric to standard

E- Add the wheel size to find your overall diameter



OE tire size:
Front-18x8.0 225/45-18 OD - 25.97
Rear- 18x8.5 245/45-18 OD - 26.68


Aftermarket Tire Size example:

Front- 18x9.0 245/40-18 OD - 25.72
Rear- 18X10.0 275/40-18 OD - 26.66

As some of you may already know this vehicle has a lot of tuning potential here is one extreme option. But it looks so good!

Front- 20x9.0 245/35-20 OD - 26.75 still under an inch upsize! no clearance issues even when dropped.
Rear- 20x10.0 285/30-20 OD - 26.73 just about the same as OE!

here is one of my personal fav's with 19x8 front and 20x10 rear! props to you bdiddy and your good taste!

https://my350z.com/forum/showthread....threadid=18966

bigworm521

???? B/C I'm facing the same issue. I'd like to stay with the Track 18's I have - can I do this size tire set up? or do I need to upgrade rims as well?

bigworm521

ANYBODY?

shaneotool

I believe that 275's are too big for the track rims. do a search, I know there are some people who upgraded their tires on stock rims. Maybe can use 255's on the rear.

safest thing to do if you're gonna keep the stock rims is just to upgrade the tires to something better in the stock sizes.