There is also a "high spot" located at the center of the lock to lock distance, like the high spot on a cam lobe...that is where you want to be. Find the approximate middle of your lock to lock distance and very slowly turn the wheel till you feel it. It acts as a stabilizer to reduce wandering while going straight, great peice of engineering. You can feel it more in a newer box as opposed to one with alot of miles.....i just learned this last year from a guy who's been doing alignments for 30+ years.