Autocross events generally involve low to medium speed races. Oftentimes, autocross races are run in empty parking lots, through streets (approved by local authorities, of course), and on airport runways not in use. Occasionally, Go Kart and other racing tracks are used. Usually, courses are set up within the boundaries of orange traffic cones, or pylons. In autocross events, only one driver participates at a time. Each driver is racing against the clock and is usually allowed three or four runs at a particular course. When a driver hits a cone it results in a time penalty of either one or two seconds. Autocross classes determine the cars involved in the event.
There are many autocross classes within the umbrella of autocross. The first class we will discuss is the Stock (S) class. Generally, cars in this class are closely related to cars driven on the streets. Any DOT-approved tires may be used. In addition, shocks that attach to stock mounting points and exhaust systems that run from the catalytic converter. Choice of brake pads is up to the car owner/driver.
The Street Touring (ST) class is relatively new and involves cars using tires with DOT ratings of 140 or better. In addition, cars must be street legal. Generally, the cars used in ST are more modified than the ones used in the Street Prepared (SP) class. Prepared (P) cars are allowed significant modifications and are usually not street-legal. To reduce weight, Prepared cars often have their seats and interiors gutted. Suspensions may be modified greatly in this autocross classes.
Street Modified (SM) cars apply to vehicles that go beyond the allowances for SP cars. In this class cars can be upgraded and modified in a variety of ways as long as they are street-legal. Modified (M) cars are split into five parts: A, B, C, D, and E. A, B, and C Modified cars are built for racing. Formula and Sport Racers fit into this category. Most are single-seat open-wheeled cars without fenders - to reduce weight. D and E Modified cars are extremely modified. Anything goes in these autocross classes, except the modification of the powertrain and floorplan layouts. Ladies (L) is a class that is reserved for women only. Autocross caters to all kinds of people and this class encourages women to participate. Street Tire (ST) cars are fitted with street tires. Rookie (R) or Novice (N) are classes designed to welcome new participants in autocross.
Before you race, check out what autocross classes your car fits so you register for the proper event. Have fun modifying your car to compete in autocross races across the country. Drive safely and don't hit any cones!