Here is how I did the measurement. First I jacked up each wheel, spun them and made a thing chalk line on the tread. Then I placed a piece of 2x2 on jack stands in front of the tires. I tacked in a small finishing nail on each side to serve as pointers to the chalk lines. Then I moverd them to the rear to see the difference. I also placed a piece of baking parchment paper with a piece of wax paper on top, under each wheel. This takes away almost all the friction between the floor and the wheels. I found that I could turn the tie rod by hand and watch the measurement chamge.
