A
spare tire is an additional
tireA tire is a ring-shaped covering that fits around a wheel to protect it and enable better vehicle performance by providing a flexible cushion that absorbs shock while keeping the wheel in close contact with the ground...
(or tyre - see
spelling differencesAmerican and British English spelling differences are one aspect of American and British English differences.- Historical origins :In the early 18th century, English spelling was not standardized. Differences became noticeable after the publishing of influential dictionaries...
) carried in a
motor vehicleA motor vehicle is a wheeled vehicle whose propulsion is provided by an engine or motor . The internal combustion engine is the most common motor choice, although electric motors or other types are sometimes used. Motor vehicles or road vehicles typically run on public roads...
as a replacement for one that goes flat, a blowout, or other emergency.
Spare tire is generally a
misnomerA misnomer is a term which suggests an interpretation that is known to be untrue. Such incorrect terms sometimes derived their names because of the form, action, or origin of the subject becoming named popularly or widely referenced—long before their true natures were known.- Sources of misnomers...
, as almost all vehicles actually carry an entire wheel as a spare, as fitting a tire to a wheel is very difficult without specialised equipment, and is not practical in an emergency. However, some spare tires ("space-saver" and "donut" types) are not meant to be driven long distances and most of them have maximum speed of around .
The early days of motor travel took place on primitive roads that were littered with stray
horseshoeA horseshoe is a U-shaped item made of metal or of modern synthetic materials, nailed or glued to the hooves of horses and some other draught animals. Like a shoe on a human, it is used to protect the animal's feet from wear and tear...
nails.
A
spare tire is an additional
tireA tire is a ring-shaped covering that fits around a wheel to protect it and enable better vehicle performance by providing a flexible cushion that absorbs shock while keeping the wheel in close contact with the ground...
(or tyre - see
spelling differencesAmerican and British English spelling differences are one aspect of American and British English differences.- Historical origins :In the early 18th century, English spelling was not standardized. Differences became noticeable after the publishing of influential dictionaries...
) carried in a
motor vehicleA motor vehicle is a wheeled vehicle whose propulsion is provided by an engine or motor . The internal combustion engine is the most common motor choice, although electric motors or other types are sometimes used. Motor vehicles or road vehicles typically run on public roads...
as a replacement for one that goes flat, a blowout, or other emergency.
Spare tire is generally a
misnomerA misnomer is a term which suggests an interpretation that is known to be untrue. Such incorrect terms sometimes derived their names because of the form, action, or origin of the subject becoming named popularly or widely referenced—long before their true natures were known.- Sources of misnomers...
, as almost all vehicles actually carry an entire wheel as a spare, as fitting a tire to a wheel is very difficult without specialised equipment, and is not practical in an emergency. However, some spare tires ("space-saver" and "donut" types) are not meant to be driven long distances and most of them have maximum speed of around .
History
The early days of motor travel took place on primitive roads that were littered with stray
horseshoeA horseshoe is a U-shaped item made of metal or of modern synthetic materials, nailed or glued to the hooves of horses and some other draught animals. Like a shoe on a human, it is used to protect the animal's feet from wear and tear...
nails. Punctures (flat tires) were all-too-common and required the motorist to remove the wheel from the car, demount the tire, patch the inner tube, re-mount the tire, inflate the tire, and re-mount the wheel. The first to equip cars with a spare wheel-and-tire assembly were the
RamblersRambler was an automobile brand name used by the Thomas B. Jeffery Company between 1900 and 1914, then by its successor, Nash Motors from 1950 to 1954, and finally by Nash's successor, American Motors Corporation from 1954 to 1969...
made by Thomas B. Jeffery Company. The Rambler's interchangeable wheel and mounted spare tire meant the motorist could quickly exchange it for the flat one. The punctured tire could then be repaired at a more convenient time and place.
The pre-mounted spare tire and wheel combination proved so popular with motorists that carrying up to two spare tires became common. Automakers often equipped cars with one or dual sidemounts. The spares were mounted behind the front fenders as they blended into the running boards (a narrow footboard serving as a step beneath the doors).
In 1941, the U.S. government prohibited spare tires on new cars. Shortages of resources caused by
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
led to quotas and laws designed to force conservation, including rubber that was produced overseas and difficult to get. A similar ban was also implemented by the U.S. during the
Korean WarThe Korean War is a war that started between North Korea and South Korea on 25 June 1950 and paused with an armistice signed 27 July, 1953...
in 1951.
Today
Contemporary vehicles may come equipped with full-size spares, limited use minispares, or have run-flat capability.
- The spare tire may be identical type and size to those on the vehicle. The spare may either be mounted on a plain steel rim or a matching road wheel as found on the vehicle. Among passenger vehicles, full-sized spares are usually provided for sport utility vehicle
A sport utility vehicle is a generic marketing term for a vehicle similar to a station wagon, but built on a light-truck chassis. Usually equipped with four-wheel drive for on- or off-road ability, and with some pretension or ability to be used as an off-road vehicle, some SUVs include the towing...
s and light truckLight truck or light duty truck is a classification for trucks or truck-based vehicles with a payload capacity of less than 4,000 pounds .- United States :...
s, since a "limited use" spare would adversely affect such vehicles with higher centers of gravity. Due to the size of the full-sized spare, it is often mounted on the outside, such as the rear door of SUVs, and occasionally on the front hood.
- Certain vehicles are provided with a "limited use" spare tire, colloquially referred to as a "donut", in an attempt to reduce cost, lower the vehicle's weight, and/or to save on the space that would be needed for a full-size spare tire. The spare is usually mounted on a plain steel rim. They are typically smaller than the normal tires on the vehicle and can only be used for limited distances because of their short life expectancy and low speed rating. As well, due to the different size of a donut compared to regular wheel, electronic stability control
Electronic stability control is a computerized technology that improves the safety of a vehicle's stability by detecting and minimizing skids. When ESC detects loss of steering control, ESC automatically applies the brakes to help "steer" the vehicle where the driver intends to go...
and traction control systems will not operate properly and should be disabled until the original wheel is restored.
- In some cases, automobiles may be equipped with run-flat tires and thus not require a separate spare tire. Other vehicles may carry a can of tire repair foam, to repair punctured tires, although these often do not work in the case of larger punctures, and are useless in the event of a blow-out.
Storage
Spare tires in automobiles are often stored in a spare tire well – a recessed area in the trunk of a vehicle, usually in the center, where the spare tire is stored while not in use. In most cars, the spare tire is secured with a bolt and
wing-nutA nut is a type of hardware fastener with a threaded hole. Nuts are almost always used opposite a mating bolt to fasten a stack of parts together. The two partners are kept together by a combination of their threads' friction, a slight stretch of the bolt, and compression of the parts...
style fastener. Usually a stiff sheet of cardboard lies on top of the spare tire well with the trunk carpet on top of it to hide the spare tire and provide a pleasant look to and a flat surface for the trunk space.
Other storage solutions include storing the spare in a cradle underneath the rear of the vehicle. This cradle is usually secured by a bolt that is accessible from inside the trunk, for security. This arrangement has several advantages over storing the tire inside the trunk, chiefly that it is not necessary to empty the contents of the trunk in order to access the wheel. The arrangement may also save space in some applications; however it has disadvantages too, such as the fact that the tire gets very dirty, making the act of changing the tire more unpleasant. The mechanism may also rust on older cars, making it very difficult to free the spare. The cradle arrangement is only practical on front wheel drive cars, as the cradle would get in the way of the rear axle on a rear or
four wheel driveThe Four Wheel Drive Auto Company, more often known as Four Wheel Drive or just FWD, was founded in 1909 in Clintonville, Wisconsin as the Badger Four-Wheel Drive Auto Company by Otto Zachow and William Besserdich....
car. A similar arrangement is also often found on trucks where the spare is often stored beneath the truck bed.
Many SUVs and
off-road vehicleAn off-road vehicle is considered to be any type of vehicle which is capable of driving on and off paved or gravel surface.
It is generally characterized by having large tires with deep, open treads and a flexible suspension, or even caterpillar tracks...
s have the spare wheel mounted externally – usually on the rear door, but others may mount them on the bonnet, the side or even the roof.
In
mid-enginedA mid-engine layout describes the placement of an automobile engine between the rear and front axles. Another term for this is mid-ship.-Benefits:The mid-engine layout is typically chosen for its relatively favorable weight distribution...
and
rear-enginedIn automobile design, a rear-engine design layout places the engine at the rear of the vehicle. The center of gravity of the engine itself is past the rear axle...
cars the spare tire is generally stored in the front boot and a dedicated spare tire well is seldom used.
Some vehicles stored the spare tire in the engine bay, such as the
Renault 14The Renault 14 is a small family car produced by the French manufacturer Renault between 1976 and 1983.Featuring front wheel drive, the 14 was developed as a competitor in the small family car segment, which had been opened up by the Volkswagen Golf...
and older Subaru vehicles, such as the
Subaru LeoneThe Subaru Leone was a compact car produced by the Japanese car manufacturer Subaru from 1971 to 1994. The word "leone" is Italian for lion....
.
Vehicles like the
Volkswagen BeetleThe Volkswagen Type 1 is an economy car produced by the German auto maker Volkswagen from 1938 until 2003. It used an air cooled rear engined rear wheel drive ....
used spare tires for ancillary purposes such as supplying air pressure for a utility system.