Theres an SAE paper you can purchase, $9.95 i think, that explains the use of radio tracers in tracking ring rotation. I havent read it in about 8 years so i dont remember all the specifics. I just remember reading the top ring spins faster than the 2nd ring, about 6 times faster if memory serves. I also dont remember how "broken in" the motor as and how many pulls they put on it to track this.