I was talking to someone the other day and they mentioned they had 2 new tires put on their car. I asked them if they really wanted to go into the ditch that bad? They answered, “What?”, I explained to them that if you mix tire tread patterns it can cause vehicle stability issues. You see, most of today’s vehicles are equipped with some kind of Vehicle Stability Control system and ABS (Anti-Lock Brakes). These systems calculate many factors and then make decisions about transmission gear changes, engine speed, braking and steering to keep you from driving beyond the vehicles limits. The problem with having tires that do not match (Tire design, manufacturer, rubber compounds, age etc.) is that all these safety systems assume that the traction or road contact is the same at each point of the vehicle. If one or more contact points are different, the systems will react incorrectly and possibly destabilize the vehicle potentially causing an accident. The moral of the story is saving a few bucks may cost you your life under certain conditions, BUY 4 TIRES!