I have a theory about why Iron Dragon's wheel assemblies jiggle around so much and conversely why the ones on PKI's Top Gun do not.
The suspended coaster axle is very similar to the axle assembly used on the multi-element coasters...an assembly that tracks very well. My theory is that the guide wheels on Iron Dragon are positioned too close together, and so the guide wheels are incapable of effectively steering the axle from both sides, allowing for excessive axle hunt. Top Gun has the 12" guide wheels, and consequently the contact points of the guide wheels are further apart.
I wonder how I could test this theory......
--Dave Althoff, Jr.