Wheel Specs/Fitment

[trevorhaymore]

Hey guys! I know I'm new here but I need some help, I'm looking into getting some new wheels for my lowered 99' Mazda. I'm currently running 15x8 -19mm offset pro comp wheels all around. I'm going to get 18s but I'm not sure what width and offset I should do, I want a flush fitment or at least somewhat flush to where the wheels are not too sucked in and not too poked out. I found a set of wheels that are 18x10 +22 in the rear and 18x9 +22 in the front. I have done a whole bunch of calculations and measurements and still cant seem to figure out the fitment, I'm trying to not run spacers but I will If I have to. My fitment right now is pretty flush and that's the fitment I'm looking for. I will include some pictures of my setup

 

[pjtoledo]

my late night sleep deprived educated guess is you'll need 1" spacers in the front with the specs given.
for the rear maybe 5/8"

since you want to keep the outside position the same, use the distance from the hub/drum/wheel mounting surface to the outer edge of the wheel as a fixed distance. use front spacing instead of back spacing for calculating the desired offset.

on the 15x8 -19mm offset (actual outside-outside =9) that's 5.25 inches front spacing. the back spacing should be 3.75"
with the centerline of the wheel being 4.5" from the front and back, the differences are 3/4" or 19mm. that's the offset.

for the 18x9-22 (actual 10 wide) the centerline is 5" from the front or rear.
to maintain the 5.25 front spacing you will have to pull the wheel out .25". (there is now a .25" air gap between the wheel & hub surface.)

and in the offset, ok. 22mm = 7/8"
the front spacing for the new wheel is 5" (centerline) minus 7/8" or about 4-1/8" the back spacing is 5"plus 7/8 or about 5-7/8"

since you desire 5.25" front spacing you're going to need 1-1/8" to make up the difference up front, more in the rear.

ideally speaking, to use no spacers the 18x9 wheel offset would be -6 offset.
it's 1" wider, only 1/2" is on the front, so change offset 1/2" / 12.7mm.

it's almost 1:30 am now, hope I got all this right.

 

[trevorhaymore]

Thank you so much for the measurements I will probably run spacers since I don't have a lot of wheel spec options in my budget