Car Tire Types Explained
Tires are classified into several standard types, based on the type of vehicle they serve. Since the manufacturing process, raw materials, and equipment vary according to the tire type, it is common for tire factories to specialize in one or more tire types. In most markets, factories that manufacture passenger and light truck radial tires are separate and distinct from those that make aircraft or off-the-road (OTR) tires
Passenger vehicles and light truck
High performance tires are designed for use at higher speeds, and more often, a more "sporty" driving style. They feature a softer rubber compound for improved traction, especially on high speed cornering. The trade off of this softer rubber is shorter tread life.
High performance street tires sometimes sacrifice wet weather handling by having shallower water channels to provide more actual rubber tread surface area for dry weather performance. The ability to provide a high level of performance on both wet and dry pavement varies widely among manufacturers, and even among tire models of the same manufacturer. This is an area of active research and development, as well as marketing.
Mud and snow
Mud and Snow, (or M+S, or M&S), is a designation applied rather arbitrarily by manufacturers for all-season and winter tires designed to provide improved performance under low temperature conditions, compared to summer tires. The tread compound is usually softer than that used in tires for summer conditions, thus providing better grip on ice and snow, but wears more quickly at higher temperatures. Tires may have well above average numbers of sipes in the tread pattern to grip the ice. There are no traction performance requirements which such a tire has to meet; M&S relates to the percentage of tread void area.
Dedicated winter tires will bear the "Mountain/Snowflake Pictograph" if designated as a winter/snow tire by the American Society for Testing & Materials. Winter tires will typically also carry the designation MS, M&S, or the words MUD AND SNOW
Some winter tires are fabricated with metal studs (consisting of a tungsten carbide or other hard material pin embedded in a base of a softer metal) for additional traction on icy roads. Between 70 to 80 studs are driven into a tire to provide better friction between the ice and the soft rubber in winter tires.
The use of studs is restricted in most countries due to the increased road wear that they cause, with the notable exception of the Nordic countries where they are commonly used during the winter season. Norway has implemented fees for using studded tires in some urban areas, and there are a few streets in some of the major cities in Sweden where studs are not allowed. Typically, studs are never used on heavier vehicles, except for some emergency vehicles like ambulances and fire trucks. Ice resurfacers also use studded tires. The upper tier classes of ice racing and rallying mandates the vehicles be equipped with studded tires.
Other winter tires rely on factors other than studding for traction on ice, e.g. highly porous or hydrophilic rubber that adheres to the wet film on the ice surface. The best stud-less winter tires offer grip close to that of studded tires during most winter conditions, with the notable exception of blank or polished ice, where they cannot match the performance of studded tires. The reason for this is that stud-less winter tires rely on unevenness in the ice surface for their sipes to grab, while studs cut into even the most polished ice surface (and in the process also make it uneven).
Studded tires are also used on bicycles, and the grip advantage on ice is similar to that from using traction sand, with the difference that there is no risk of blank spots when using studded tires. Quality tire manufacturers use studs with hard center pins also for bicycle tires, and just like their automobile counterparts, those studs will continue to protrude from the tire even after many years of usage on bare pavement. There are also low-quality studded bicycle tires being sold that have studs that lack the hard-metal center pin (there is still a center pin, but it is not made of hard metal). Such studs can wear out within a few weeks of cycling on dry pavement.
Some jurisdictions may require snow tires or tire chains on vehicles driven in certain areas during extreme weather conditions.
Mud tires are specialty tires with large, chunky tread patterns designed to bite into muddy surfaces. The large, open design also allows mud to clear quickly from between the lugs. Mud terrain tires also tend to be wider than other tires, to spread the weight of the vehicle over a greater area to prevent the vehicle from sinking too deeply into the mud. However in reasonable amounts of mud and snow, tires should be thinner. Being thinner, the tire will have more pressure on the road surface, thus allowing the tires to penetrate the snow layer and grip harder snow or road surface beneath. This does not compensate when the snow is too deep for such penetration, where the vehicle will sink into the snow and plough the snow in front and eventually pack it beneath it until the wheels no longer have traction. In this case, wider tires are preferred, as they have a larger contact patch and are better able to 'float' on top of the mud or snow.
The All Season tire classification is a compromise between one developed for use on dry and wet roads during summer and one developed for use under winter conditions. The type of rubber and the tread pattern best suited for use under summer conditions cannot, for technical reasons, give good performance on snow and ice. The all-season tire is a compromise, and is neither an excellent summer tire nor an excellent winter tire. They have, however, become ubiquitous as original and replacement equipment on automobiles marketed in the United States, due to their convenience and their adequate performance in most situations. Even so, in other parts of the world, like Germany, it is common to have a designated tire set for winter and summer. All-Season tires are also marked for mud and snow the same as winter tires but rarely with a snowflake. Owing to the compromise with performance during summer, winter performance is usually poorer than a winter tire.
All-terrain tires are typically used on SUVs and light trucks. These tires often have stiffer sidewalls for greater resistance against puncture when traveling off-road, the tread pattern offers wider spacing than all-season tires to remove mud from the tread. Many tires in the all-terrain category are designed primarily for on-road use, particularly all-terrain tires that are originally sold with the vehicle.
Some vehicles carry a spare tire, already mounted on a wheel, to be used in the event of flat tire or blowout. Minispare, or "space-saver spare" tires are smaller than normal tires to save on trunk/boot space, gas mileage, weight, and cost. Minispares have a short life expectancy and a low speed rating, often below 60 miles per hour (97 km/h).
Domestic Trailers (including camping trailers) for use on public highways often have different tires than those seen on cars. Often they are bias ply rather than radial tires, and they often don't have as aggressive a tread pattern as standard road tires. They are not built for high traction in most cases, because in most cases it is not vital that trailer tires have as good a traction as that of the vehicle towing the trailer.
Several innovative designs have been introduced that permit tires to run safely with no air for a limited range at a limited speed. These tires typically feature strong, load-supporting sidewalls. An infamous example of an alternate run-flat technology has plastic load-bearing inserts attached to the rim instead of the reinforced sidewalls.
A disadvantage is that run-flat tires cannot be repaired if a puncture occurs, this is due to manufacturer's informing the automotive industry that you cannot tell what kind of state the sidewall is in due to the compacted sidewall of rubber.
Heavy duty truck
Heavy duty tires are also referred to as Truck/Bus tires. These are the tire sizes used on vehicles such as commercial freight trucks, dump trucks, and passenger buses. Truck tires are sub-categorized into specialties according to vehicle position such as steering, drive axle, and trailer. Each type is designed with the reinforcements, material compounds, and tread patterns that best optimize the tire performance. A relatively new concept is the use of "Super Singles" or Wide Singles. Generally in a dual configuration, there are 2 tires per position, each between 275 mm-295 mm wide. The Super Single replaces these with a single tire, usually 455 mm wide. This allows for less tread to be contacting the ground and also eliminates 2 sidewalls per position. Along with the weight savings of about 91 kilograms (200 lb) per axle, this enables vehicles using these to improve fuel economy.
Off-the-road (OTR) tires include tires for construction vehicles such as wheel loaders, backhoes, graders, trenchers, and the like; as well as large mining trucks. OTR tires can be of either bias or radial construction although the industry is trending toward increasing use of radial. Bias OTR tires are built with a large number of reinforcing plies to withstand severe service conditions and high loads.
Dramatically increasing commodity prices has led to shortages of new tires. As a consequence, multi-million dollar trucks can be idled for lack of tires, costing mines millions of dollars in lost productivity. This has led to a stronger effort to recycle old OTR tires. As of 2008, a new OTR tire can cost up to $50,000; retread tires are sold at half the price of new tires, and last 80% as long. Retreading an OTR tire is labor intensive. First, the retreading technician must place the old tire in a buffing machine to remove what remains of the old tread; "skiving" follows this, which is the removal, by hand, of material the buffing misses. Next, the technician must inspect the tire, repairing defects. Lastly, the technician fills holes in the tire with rubber, applies a cement gum adhesive, and places the tire on a machine that will apply a new tread.
Agricultural and off-road flotation tires
The agricultural tire classification includes tires used on farm vehicles, typically tractors and specialty vehicles like harvesters. Driven wheels have very deep, widely spaced lugs to allow the tire to grip soil easily.
For off-road driving in a passenger vehicle, such as in mud, sand, or deep snow, high flotation tires are typically used. Flotation tires are not the same as M+S tires, as they are designed for low speeds and full-time off road use rather than muddy and snow-covered roads. Flotation tires also help traction in swampy environments and where soil compaction is a concern, featuring large footprints at low inflation pressures to spread out the area where the rubber meets the ground. Knobby tires are particularly useful where the ground consists of loose particles that can be displaced by the knobs. Although the low pressure improves traction in many types of terrain, adjustments may need to be made for hard surfaces like paved and unpaved roads. Vehicles that use flotation tires for rock climbing are susceptible to flat tires in which the tire pops off the rim, breaking the "bead."
Racing tires are highly specialized according to vehicle and race track conditions. This classification includes tires for drag racing, Auto-x, drifting, Time Attack, Road Racing – as well as the large-market race tires for Formula One, IndyCar, NASCAR, V8 Supercars, WRC, MotoGP and the like. Tires are specially engineered for specific race tracks according to surface conditions, cornering loads, and track temperature. Racing tires often are engineered to minimum weight targets, so tires for a 500 miles (800 km) race may run only 100 miles (160 km) before a tire change. Some tire makers invest heavily in race tire development as part of the company's marketing strategy and a means of advertising to attract customers.
Racing tires often are not legal for normal highway use.
Sport Street – these tires are for aggressive street riders that spend most of their time carving corners on public roadways. These tires do not have a long life, but in turn have better traction in high speed cornering. Street and sport street tires have good traction even when cold, but when warmed too much, can actually lose traction as their internal temperature increases.
Track or Slick – these tires are for track days or races. They have more of a triangular form, which in turn gives a larger contact patch while leaned over. These tires are not recommended for the street by manufacturers, and are known to have a shorter life on the street. Due to the triangulation of the tire, there will be less contact patch in the center, causing the tire to develop a flat spot quicker when used to ride on straightaways for long periods of time and have no tread so they lose almost all grip in wet conditions. Racing slicks are also made of a harder rubber compound and do not provide as much traction as street tires until warmed to a higher internal temperature than street tires normally operate at. Most street riding will not put a sufficient amount of friction on the tire to maintain the optimal tire temperature, especially in colder climates and in spring and fall.