Nice Work, yeah you may have to do a little tutorial on that. Thats one hell of a test!!! There are some minor problems in there near the end where it looks as if the tread is a little loose. I know tanks are pretty darn heavy so for the tread to seperate from the wheel seems like it could use some tweaking, but other then that its Great!!
heres a link
http://www.army.forces.gc.ca/Land_Fo...ks_800x600.jpg
see how the tread doesnt drop from the wheels? maybe that will help