Racing tires are car tires designed especially to give high-performance in racing. Tire design and requirements varies considerably based on what type of racing is being done. Racing tires are designed for speed and performance rather than durability and often need to be changed after about 100 miles (160.9 km), whereas regular street tires are built to last and may perform well for several years.
Many types of racing tires differ so strongly from regular tires that they are prohibited on regular roads or for normal driving purpose. This standard is not highly debated however, as racing tires are usually quite expensive and would be wasted on regular roads. To optimize performance at high speed, racing tires are usually thinner, somewhat lighter, and filled with low-moisture air or even nitrogen compounds. These features, while great for racing, are ill-suited to regular driving.
Due to a high rate of accidents, many racing tires feature a unique accessory called a safety spare. This tubeless tire actually resides inside the main tire, ready to work in case of an emergency. If a tire blows out, the safety spare will allow a driver to return to the pit or, at the very least, get out of the way. In most official races, safety spares are a requirement, but in races under a mile they may be an optional piece of equipment.
Racing tires are designed and built differently for different types of races. Track shape and track material are two deciding factors in what type of tires are needed. Dirt track racing tires feature more defined tread patterns than asphalt tires, and are often slightly larger in circumference. Tires for oval-shaped tracks are designed to perform differently than those built for freeform tracks or street racing.
In dirt racing, typical track condition and even soil makeup can be a major part of choosing tires. Most dirt tires feature a grooved tread pattern that helps maximize performance on dry dirt. If the track is in a wet area, however, or if the dirt present is moist or wet, deep grooves can become clogged and impair performance. For this reason, choosing dirt racing tires is often a more complicated decision than choosing asphalt tires.
Most races that are run by a professional organization have very specific guidelines and requirements as to what tires are and are not allowed. Failure to follow these rules specifically can lead to ejection from the race, as well as possible probation or suspension from the league. Tire requirements are an attempt to increase safety and keep all drivers on a relatively equal playing field from an equipment standpoint. By requiring standardized equipment, track officials ensure that it is skill rather than superior technology that will usually determine the outcome of the race.