I have been getting some speed wobbles lately. It has to be under certain conditions like a head/cross wind while descending down a long and fairly steep straight road. I am usually in the drops and if I hit the brakes to shed speed, my bike starts to wobble. It can be scary. I have a 2005 Specialized S-works bike and all the parts are in great shape. My hubs and headset have no play in them. Got any suggestions? I have changed wheelsets to try and fix this problem, but its still there.