slower to swerve or go into a tight curve, and it also makes it slower to turn straight again. The pitch angular inertia detracts from the ability of the suspension to keep front and back tire loadings constant on uneven surfaces and therefore contributes to bump steer. Angular inertia is an integral over the square of the distance from the center of gravity, so it favors small cars even though the lever arms (wheelbase and track) also increase with scale. (Since cars have reasonable symmetrical shapes, the off-diagonal terms of the angular inertia tensor can usually be ignored.) Mass near the ends of a car can be avoided, without re-designing it to be shorter, by the use of light materials for bumpers and fenders or by deleting them entirely. If most of the weight is in the middle of the car then the vehicle will be easier to spin, and therefore will react quicker to a turn. Suspension Automobile suspensions have many variable characteristics, which are generally different in the front and rear and all of which affect handling. Some of these are: spring rate, damping, straight ahead camber angle, camber change with wheel travel, roll center height and the flexibility and vibration modes of the suspension elements. Suspension also affects unsprung weight. Many cars have suspension that connects the wheels on the two sides, either by a sway bar and/or by a solid axle. The Citroën 2CV has interaction between the front and rear suspension. The flexing of the frame interacts with the suspension. (See below.) Spring rate The following types of springs are commonly used for automobile suspension, variable rate springs and linear rate springs. When a load is applied to a linear rate spring the spring compresses an amount directly proportional to the load applied. This type of spring is commonly used in road racing applications when ride quality is not a concern. A linear spring will behave the same at all times. This provides predictable handling characteristics during high speed cornering, acceleration and braking. Variable springs have low initial springs rates. The spring rate gradually increases as it is compressed. In simple terms the spring becomes stiffer as it is compressed. The ends of the spring are wound tighter to produce a lower spring rate. When driving this cushions small road imperfections improving ride quality. However once the spring is compressed to a certain point the