How to animate tank treads in 2D picture?

Question

hi
I have a .psd picture of a tank and try to animate it in AE by rotating its wheels and tread (or track?). The only solution i have come up with is to slightly change tread layer's x and y positions in every frame, making it to vibrate. However it does not create rotation illusion which i'm after - the tread vibrates, but doeas not revolves around the wheels.
If there are other solutions to make tread layer rotate around tank's wheels, i would be glad to hear about them.
All 7 tank's wheels are separate layers and the tread layer is above them. The rest of the tank's layer is above tread layer
thank you

Answer 1

I know it's late....
but since it's a 2D front view, i would try and make a solid layer, put a VEGAS effect on top of it, draw a mask around the tanks track, then probabely do the whole animation of the tank
wheels and track (its a mask so you can animate separate vertex points). And when the whole animation is set and done i would precompose the track solid layer and move the
mask and effects to the PRECOMPOSED layer. Now back in the original layer i would put some effects (bevel emboss?) on the precomposed track.
I think you could skip the vegas and mask effect and do the shape layer with segemented stroke animation.
But VEGAS does give nice effect in this case.
yeah i know it's late
artur