I have a set of rims and they are 18x8 with a 40 offset. I want to make them flush but with no fender rolling and rubbing. I'm planning to add wheel spacers but I don't know if I should just go with 5mm or probably 5mm in the front and 15mm in the rear. What do you guys think?

 

i might go 10 in the front and 15 in back...

i have 18x8 with 37 offest with 5mm in front and i want a bit more...

 

^^^thats the thing. i would go with 10mm but as of now, there is no company that makes 10mm. so with the 5mm in the front, that brought your offset down to 32mm in the fronts right? are you lowered? rubbing?

 

bump!

 

I would go with 5mms in the rear and front....

 

but i think the rear is more tucked in than the front.

 

bump!

 

x2

 

what youre asking is not possible.
you will have to roll fenders or put up with rubbing or both if you want to be flush. i'd put 5mm spacers in the front and rear. you'll be eqivalent to 18x8 et35 for a fairly nice stance, but not completely flush. 15mm in the front and 20mm in the rear will put you really flush.

 

or 25 mm with stock wheels =X yea thats right i did that, hella flush haha mad rubbin tho. even with rolled/pulled fenders... btw i have to smooth out my rear fenders theya re a little wavey.

 

it will look good, but it's gonna rub on dips

 

It's going to rub. I have 8" +35 and it rubs over every bump.