What widths do you want? I can help once we have that down.


I can also explain...If you teach a man to fish, right?


Offsets aren't particularly hard to work with, but many people struggle because they have never had them explained well.

When you are installing a set of rims, there are generally two things you need to worry about. One is inner clearance, and the other is outer clearance.

I'm going to assume you aren't doing anything truly crazy, which means we can ignore the inner clearance and just worry about the outer clearance, which will make things a little bit easier.

Your wheel basically looks like this, with the right side being the face, and the bulge representing where the wheel mounts. The spacing between the mounting face and the center of the wheel is the offset.

http://img.tapatalk.com/a69372de-ccea-834f.jpg

If this number is zero, the mounting face is in the center of the wheel. If it is positive, it is on the face's side of center,(right, in this picture) and if it is negative, the mounting point is on half of the rim away from the face.

This basically translates to meaning a higher (positive) offset brings your wheel in tighter to the car, while a lower (or negative) offset spaces the wheel out.

To start, let's look at the stock 18" rim sizes:

F: 8" ; +43mm
R: 9" ; +15mm

So our outside width for the stock rims is:

F: = 4" - 43mm = 5.86cm
R: = 4.5" - 15mm = 9.93cm

Of course, stock rims aren't very aggressive, and most people want something that pushes them out a bit more.

25mm spacer front and rear gives us something like this:


F: = 4" - 18mm = 8.36cm
R: = 4.5" +10mm = 10.43cm

And a more aggressive 9.5/15 (this may actually rub) || 10.5/5 gives us:


F: = 4.75 - 15mm = 10.565cm
R: = 5.25 - 5mm = 12.835cm


The long and the short of this is that what offset you need is going to vary dramatically based on the width of the wheel you need, and the look you want.

Something aggressive might be in the range of:
F: 9.5" , +18
R: 10.5, +5


If you want to stay with stock widths and keep the offsets, you have those numbers. If you want to space them out more, just subtract out how much extra spacing you want* (ie, 25mm spacer takes the front to a +18 and the rear to a -10).

These numbers should give you an idea how various offsets will sit

Holy Explanation Batman! Thank you sir. I didn't even know that I didn't know some of that info. Rep'd! :tiphat:

Damn why is that Mustang fanboy helping Z owners out? :mad:

June 7th is a trolling holiday :roflpuke2:

lol @ you calling that post trolling :bowrofl:

I talked to someone at Modbargains yesterday and after explaining the tire/wheel size I'd like to stay at, they recommended 18x8.5 & 18x9.0. Based on this info, what would you recommend I do about the offset?

Thank you for the explanation!! Will definitely rep when I get a chance. :tup:

Wheel Tech - Offset

offset. also read the other FAQ's. good info there.

:icon18:

To stay with stock fitments, you would want +15 in the rear and about 50mm up front. There's probably room to go to about a -10 rear and 25-30mm up front.

18x8.5 and 18x9 are good for snow tires.


get 18x9 and 18x10's minimum. front 30-35mm offset, rear 15-20mm offset for stock height.

Left it home today. Weather forecast on my phone said thunderstorms. I have free time for lunch and it's gorgeous out... figures!

lol, which app are you using? i use weatherbug and it's pretty accurate. better than weatherchannel and other apps ive tried. trick is to see radar in motion and barometric pressure. :)

Looks good. Have you tried it out yet? Does the mic pick up any vibration or noise from the bar?

Edit - oops, I assumed this is for the mic...

Will that work with these tires?

Front Size

225/50ZR18XL 99Y B

Rear Size

245/45ZR18XL 100Y B

She's trying to keep tires.



I personally recommend just running out the new tires and going all out when those wear out though.