I used that method this weekend to confirm my suspicion that something was out of whack on my 544's front suspension. The top of the driver's side front wheel ticks out about 3/8 of an inch more than the bottom (the other side is about 1/8 of an inch inward - probably close to correct). I then proceeded to play around with the adjustment (much nicer than a 120 - an offcenter metal bushing with a crimp bolt. Loosen the crimp bolt and rotate to milimeter precision). But it was already full inward. So I started measuring from here to there and finally determined I have a bent spindlt. On the 544 the upper pivot is at the end of a slender graceful arm that goes around the upper kingpin bushing and up to the upper pivot. Its bent about 1/4 inch to the inside on mine. Some previous owner must have thunked a curb. So I'll have to live with worn outer edges on tires in that spot until I get a new spindle.