I tried searching and didn't find what a definition or explanation on offset.

I'm looking to buy my first set of wheels for my z after 4 years. my car is all stock suspension im gonna get 18x9.5 all the way around i want to know if i can run a 245/45r18 front and a 265/40r18 rear or possible bigger? but i have been reading it may depend on the offset. I want to know how if you go with a +10 in the rear or a +30 which will allow a bigger tire and the main question how?

any help would be really appreciated i'm looking to buy a set of used wheels off here but i don't want to buy them have to find out i need to roll my fenders thanks guys.

 

Offset is a measurement from the centerline of the wheel to the wheel hub mounting surface. For a given wheel width, as the offset value gets lower (and negative), the centerline of the wheel is moving farther outward from the center of the car. Then of course as the offset value increases, the centerline of the wheel is getting closer to the center of the car.

Do a google images search for "wheel offset". A bunch of diagrams will pop up and should be a good guide for you.

 

ok thanks i think i get it so by getting a higher positive offset can i make it so that the wheel edge will come closer to flush with the body?

i'm looking to get p45r 18x9.5 all around with a +20 offset and i seen a guy on here that did and he had to roll his fenders is that only because he went with such a wide tire and high aspec ratio? can i run a 265/40r18 on the rear without rolling or do i have to get a 265/35r18

https://my350z.com/forum/wheels-and-...-question.html

 

i beleive you have it backwards. The closer to zero and negative offset the closer to the feder or outside of your car. The higher towards 100 fir example the closer to the inside of car.

 

ok the way i have been seeing it is when a +30 say is used i find it has a larger concave then if you go with say + 10 when i said bring it closer to the fender i mean the lip of the wheel not the center.

 

Normally when the offset is +10 it will have a deeper concave than +30. Also, it depends on the rims itself. All stlyes are different. To bring the lip of the wheel closer to the fender you need the right wheel width and offset to have a flush look. You should try to look in the wheel section it will help you visualize it more. It definately helped me out.

 

There are other factors that contribute to face concavity, including wheel width and diameter. And sometimes concavity is unaffected by offset. For example, a 19x9.5 Volk TE37 +22 offset versus +12 offset has no discernible difference in face concavity, but the lip on the +12 is wider (i.e. sticks out farther from the center of the car). In that case, they essentially held the face in place and slid the barrel 10mm farther outward, changing the offset from +22 to +12. But that's just one example. Sometimes concavity will be modified to get clearance (backspacing) for brake calipers. Wheel design is somewhat of an art.

 

Front tire is taller than rear. Is this what you want?

 

9.5 +20 will work great without a roll , you will want a 245 or 255\40-18 up front and a 275/40-18 out back.

 

Please read the Top 100 FAQ it is clearly explained there