The geometry of the bike has a lot to do with its stability. I do not remember positively which causes low speed stability and which causes high speed stability, but they have their roots in rake and trail. Adjusting trail to a higher figure (Or lower if my memory is wrong) makes low speed stability better, while the opposite, less trail (or more if I got them mixed up) makes the bike more stable at high speed. If I remember correctly a good example of low speed stability, high trail is a shopping cart wheel. Likewise if my memory is correct more rake is more stable at low speed, andless is more stable at high speed, hence racing motorcycles are more upright in front than cruisers.