When changing tire diameters and suspensions, using the stock factory axle centerlines can make the wheels & tire look either to far back or forward in the wheel opening.

Here are the proper steps to make sure that when you’re done, your wheels and tires will look correct.

Step 1: After removing the original front or rear suspension, re-install the fenders and position the vehicle at ride height and rake. Place the correct diameter wheel/tire (or plywood circles the diameter of the tires you plan on using) in the fender opening and block into desired place.

Step 2: With the wheel/tire in position, extend a heavy string (chalk line, twine, etc.) across from the wheel’s hub centers. Using a plumb bob, hang off the side of the frame rail to the center of the string. Mark the plumb bob line on the frame rail. To insure that the ACL marks are square with the frame, measure from a common point on the frame (crossmember, bolt holes, etc.) to the ACL mark. The distance should equal on each side.