offsets have a lot to do with wheel fitment, and alignment can also have a big impact on fitting wheels.

offset is how far the hub surface of the wheel is moved either toward the outside or inside of the wheel. 0 offset means the hub is dead centered in the middle of the width of the wheel. positive offset moves the hub toward the face of the wheel, basically moving the wheel itself in closer to the car. negative offset moves the hub surface toward the back of the wheel, which moves the wheel itself out away from the chassis.

the first step to figuring out what wheels you can run is to measure or approximate the width of wheel you can fit under the fender (take into account suspension/chassis clearance or anything else that could get in the way). after you figure that part out you need to take a straightedge and lay it vertical across the hub surface on the car. measure from the straightedge to the fender. after you have those measurements you can figure things out.


let's use theoretical numbers for this... so we'll say a 10" wide wheel is what will fit, and you have 6.5" from your hub surface to the edge of the fender.

it's easier if you break down your measurements into Millimeters since that's what the offset is generally given in.

1in=25.4mm roughly... so a 254mm wide wheel and you have you have 165.1mm of space to your fender to fill. to have this wheel flush, you need 165mm of the wheel foreward of the hub, and the rest (254mm-165mm=89mm) behind the hub. the wheel we're using here with 0 offset would have 127mm on either side of the hub (254/2) so to figure out the offset from 0 we subtract 127(centerline)-89(backspacing). this would give this theoretical wheel an offset of -38.

hope that makes some sense, it's easier than it sounds you just have to take a couple measurements and decide what you want then you can figure out what's close.