Well Ethan, this is what I did to get an OVL (over all length) from steering knuckle to knuckle. Start by getting the tires as parallel to each other and as parallel to the car as you can. For getting them parallel to the car this a merely a visual check. Now for the tires, you can do this by measuring the center line of the front driver side tire over to the center line front side of the passenger tire. Then measure the center line back of the tire on the driver side over to the center line of the back of the tire on the passenger side. This can all be preformed using a tape measure. (and some help recommended) Once you have managed your best efforts in making the tires parallel to each other along with being parallel to the vehicle. Place the tape measure where the tie rod end goes in the steering knuckle, then pull the tape measure over to the other side. This will provide a rough estimate on your over all length. Once completed you will have to take it in for an alignment for the final adjustments.