There is a video somewhere wherein the mechanic explains that the easiest way to adjust the belt is with the tire constantly spinning with the weight of the spyder on it as in being on a "treadmill". He made the treadmill from 2 industrial rollers and aluminum frames/spacers on either side. I know he is right about this as every time I had my alignment perfect, it would walk off track and out of alignment when I put the bike back on the ground and took it for a ride. SOOOOO FRUSTRATING.... You know don't you??
So, I finally got it. A year later, stone through the belt, installed a new belt and THAT was more fun than a person deserves! WTH?? I finally got it but, shortly afterward I found this post (on this forum) and a video with this guy using the "treadmill" method. SO, I ordered myself some 1/2" plate aluminum and found some industrial rollers that would hold the weight of the Spyder with room to spare. I haven't built my treadmill yet but, I'm going to have to and soon...
...because, last year for my yearly Spyder upgrade, I thought I would treat myself to a 3-wheel laser alignment. I took it to a dealer in Hanover, PA. I have no idea what they did to the Spyder but, when I got it back, the belt was rubbing the inside flange after a short test ride. I took it immediately back. They adjusted... still no good. Took it back, ...still no good. OH... and it had "acquired" a new BAD vibration. I spent a lot of money to have my Spyder F'd up. The fourth time I took it back, the mechanic was VERY annoyed (yeah... I KNOW how he felt but, I thought HE was the expert... that's why I was paying the big bucks right??) so, I told them to just forget it. I've ridden it a few thousands of miles and no abnormal belt wear. Like I said, I must SOON build my treadmill!
Good luck all...