Hello, My first post and it's going to be a question =) I hope I can get some replies. Here we go :- I'm constructing a simulation of a motorcycle with rider and I have encountered a problem with oscillation (lack of stability) that I just can't find a solution for. Basically the bike will run in a straight line fine, and it will turn and lean into a corner ok (I'm currently working my model with two masses - One for the bike and one for the rider, I'm balancing and leaning the bike by moving the mass of the rider around). But it then gets into a cycle of oscillation that eventually leads to the bike falling over or getting into even worse conditions of pure instability. The problem centers around the model slightly overshooting it's desired lean so the mass of the rider constantly shifts from side to side to compensate thus leading to the oscillations. I've been trawling the net, books and other sources and have reached a brick wall. There must be a solution out there somewhere =) Hence my post here, to get some other minds on the problem and hopefully a post or two that will get me off in the right direction (so to speak). btw - great forum you have here..