Thats a good one. Come to think of it, I dont see any tricycles with chains. Wonder where I got this image with a chain. Anyways, I still have the problem with the chain - tricycle or bicycle!!. The tank tread I saw on google is for motion path animation which I have alread done for a previous model of mine .. an escalator. This is linked to the frames with a start and end time and is animated when you play. What I am looking for is to have the chain linked to the cycle so that when I move the cycle, the chain starts rotating. Just like the ones we see. Cheers GP