A shorter tire drops top speed but helps acceleration. A wider tire helps cornering in dry weather, but a thin tire is better for snow and sand because it cuts through the material instead of driving over it. Changing tire height is similar to changing gear ratios, taller tires take less rpm to achieve a given speed so gas mileage can go up, but its similar to having a tall gear ratio which can kill take off acceleration. Low profile tires help cornering because the tire wall is shorter and stiffer so they don't flex during cornering.
Wider tyres lay down more rubber than thinner ones which improves the grip. This vastly improves braking, cornering and acceleration. This is why if you look at the width of the tyres on a porsche they are almost twice the width of a normal car. Having wider tyres will allow you to use more throttle without spinning the wheels. Choose your tyre size carefully though, adding 17" rims to a citroen saxo will have a negative affect on the cars cornering abilities. Unfortunately some people do not think about this.
Tire height changes overall final gear ratio Using 26" tall tire as a std. 1" diff in height will have the effect on rate of accel as a .06:1 change in gear ratio Taller makes gear ratio higher (lower number) Short makes it act like a lower (high number) gear ratio Wider tires has more rubber, more sufrace area. They grip the road better
