tire clearance issues

1. You have a baseline with what you have.
2. Measure how far out the tires are to the wheel opening.
3. Measure how much space you have between the inside of the tire and the spring
4. Measure mow much space you have between the tire and the inner fender well.

With these numbers you can determine what back spacing you need verses the back spacing you have now.

Example.
These are only numbers for the example
Tire sticks out 1 inch
There is 2 inches from inside of tire to inner fender well
There is 1.75" inside of tire to spring

Your current back spacing is 3"

You need to move the wheel /tire combo inboard by 1.25 inches to clear the fender lip.

You have 1.75" on the inside.

So when you get your new wheels with 4.25 back spacing (existing 3 plus the 1.25 you need to move the tire) you will have 1/4" on the outside and 1/2" on the inside clearance.