Wikicars - User contributions [en]

Tires

2010-02-23T11:14:00Z

Doggyowner: /* Sources and References - External Links */

A '''tyre''' or '''tire''' is a device covering the circumference of a [[wheel]]. It is an essential part of most ground vehicles and is used to dampen the oscillations caused by irregularities in the road surface, to protect the [[wheel]] from wear and tear as well as to provide a high-friction bond between the car and the road to improve acceleration and handling. Today most tires, especially those fitted to motor vehicles, are manufactured from synthetic rubber, however other materials such as steel may be used.
[[Image:FirestoneTire.jpeg|thumb|Firestone tire]]

==History==
[[Image:Tire_repair_shop.JPG|thumb|300px|left|A tire repair shop in Vologda, Russia. The text painted says "Tire mounting" (''Shinomontazh'')]]
For most of history wheels had very little in the way of shock absorption and journeys were very bumpy and uncomfortable.
The modern tire came about in stages in the 19th century.

In 1844, Charles Goodyear invented vulcanization, the process that would later be used to produce cured rubber tires.

John Boyd Dunlop, a Scottish veterinary surgeon working in Belfast, Ireland, is mainly recognized as the father of the modern tire, although he was not the first to come up with the idea. In 1845 the first pneumatic (inflatable) tire was patented by fellow Scotsman, the engineer Robert William Thomson, born in Stonehaven, Scotland, as the '''Aerial Wheel'''. This invention consisted of a canvas inner tube surrounded by a leather outer tire. The tire gave a good ride, but there were so many manufacturing and fitting problems that the idea had to be abandoned. John Dunlop re-invented the tire for his ten year old son's tricycle in 1887 and was awarded a patent for his tire in 1888 (rescinded 1890). Dunlop's tire had a modified leather hosepipe as an inner tube and rubber treads. It wasn't long before rubber inner tubes were invented.

Because neither bicycles nor [[automobile]]s had been invented when Thomson produced his tire, that tire was only applied to horse drawn carriages. By Dunlop's time, the bicycle had been fully developed (see [[Land Rover]]) and it proved a far more suitable application for pneumatic tires. Pneumatic tires were first installed on aircraft in 1906.

Dunlop partnered with William Harvey du Cros to form a company which later became the ''Dunlop Rubber Company'' to produce his invention. The invention quickly caught on for bicycles and was later adapted for use on [[automobile|car]]s. Dunlop is now a subsidiary of the Goodyear Tire and Rubber Company.

The radial tire was invented by Michelin, a French company, in 1946, but did not see wide use in the United States, the largest market at that time, until the 1970s. This type of tire uses parallel carcass plies for the sidewalls and crossed belts for the crown of the tire. All modern car tires are now radial. In 2005, Michelin was reported to be attempting to develop a tire and wheel combination, the Tweel, which does not use air.

== Etymology ==
According to the ''Oxford English Dictionary'', quoted in ''Fowler's Modern English Usage'', the word is a shortening of ''attire'', and the British spelling ''tyre'' is a recent divergence from historical tradition. Fowler also notes that the altered spelling ''tyre'' originally met with resistance from conservative British institutions such as ''The Times'' newspaper.

== Nomenclature ==
The outer perimeter of the tire, often called the crown, has various designs of jagged shaped grooves in it, known as the '''tread'''. These grooves are especially useful during weather with rain (or snow). The water from the rain is compressed into the grooves by the vehicle's weight, providing better traction in the tire-to-road contact. Without such grooves, a layer or film of water would form between the wet road and the tire's surface, which would cause [[hydroplaning]], substantially reducing traction. However, if the road is dry, treads actually reduce grip since they reduce the contact area, hence why 'slicks' are used in [[motor racing]]. Traction is especially important to achieve good [[brake|braking]] or high-speed cornering. The depth of these grooves essentially constitutes the [[tread]] depth. Varying due to wear during the lifetime of the car. When the tread on the outer perimeter of the tire wears away, reducing the tread depth, the tire should be replaced. The ''sidewalls'' are the sections of the tire which are between the crown and the inner circular edges of the tire contacting the rim. To avoid tearing at these inner edges, particularly when the tire is being mounted, there are a number of concentric steel wires buried inside the rubber at both inner edges of the tire. This inner rim is called the ''bead''.

Some air-filled tires, especially those used with [[spoked wheels]] such as on bicycles, or on vehicles travelling on rough roads, have an '''inner tube'''; this was also formerly the case of [[automobile]] tires. This is a fully sealed rubber tube with a valve to control flow of air in and out. Others, including modern radial tires, use a seal between the metal wheel and the tire to maintain the internal air pressure (''tubeless tire''). This method, however, tends to fail desperately if the vehicle is used on rough roads as a small bend on the rim (metal wheel) will result in deflation. The inner tubes are usually made of halobutyl rubber, because of its suitable mechanical properties and excellent impermeability for air.

Pneumatic tires generally have reinforcing threads in them; based on the orientation of the threads, they are classified as [[bias-ply]]/[[cross ply]] or [[radial tire|radial]]. Tires with radial yarns (known as '''radial tires''') are standard for almost all modern [[automobile|automobiles]].

==Tire types==
===Wagon tires===
The earliest tires were hoops of metal placed around wagon wheels. The tire was heated in a forge, placed on the wheel and quenched, causing the metal to shrink, which drew the rim against the [[spoke]]s and provided stiffness to the wheel. This work was done by a [[wheelwright]], a craftsman who specialized in making wagon wheels.

===Pneumatic tires===
Air-filled tires are known as pneumatic tires, and these are the type in almost universal use today. Pneumatic tires are made of a flexible elastomer material such as rubber with reinforcing threads/wires inside the elastomer material. The air compresses as the wheel goes over a bump and acts as a shock absorber. Tires are inflated through a valve, typically a Schrader valve on [[automobile]]s and most bicycle tires, or a Presta valve on high performance bicycles. Attempts have been made to make various types of solid tire but none has so far met with much success. The air in conventional pneumatic tires acts as a near constant rate spring because the decrease in the tire's volume as the tire compresses over a bump is minimal. "''Airless''" tires usually employ a type of foam or sponge like construction which consists of a large number of small air filled cells. As a result compression is localised within the tire and the effective spring rate rises sharply as the tire compresses. The result is a tire which is less forgiving, particularly with regards to sharp transient bumps and provides poor ride and handling characteristics. The "''steering feel''" of such tires is also different from that of pneumatic tires, as their solidity does not allow the amount of torsion that exists in the carcass of a pneumatic tire under [[steering]] forces, and the resultant sensory feedback through the steering apparatus; as a result they feel as if they are pivoting on bearings at the contact point. They are more popular for bicycles than for [[automobile]]s, which have tires which are much more robust and immune to puncture.

The common motor vehicle tire is mounted around a steel or aluminum alloy [[wheel]] at service stations or repair shops for vehicles using a special tire mounting apparatus while the wheel is off the vehicle. After mounting, the tire is inflated (pressurized) with air through the valve stem to manufacturer's specified pressure, which is more than atmospheric pressure. The [[wheel]] and tire assembly are then attached to the vehicle through a number of holes in the wheel using '''lug nuts'''. Because tires are often not made with perfectly even mass all around the tire, a special '''tire-balancing''' apparatus at a repair shop spins the wheel with the tire to determine where small weights should be attached to the outer edge of the rim to balance out the wheel. Such tire balancing with these kind of weights avoids vibration when the vehicle is driven at higher speeds.

With the introduction of radial tires, however, it was found that some vibrations could not be cured by adding balance weights. This was because the structure and manufacture of a radial tire lends itself to the problems of variation in stiffnes around the tire. These variations are measured as ''Radial Force Variation'' and ''Lateral Force Variation'', which are measured on a ''Force Variation Machine'' at the end of the manufacturing process. Tires outside the specified limits for RFV and LFV are rejected.
This is known in general throughout the industry as "''Tire Uniformity''."

===[[Automobile]] and [[Trucks|truck]] tires===
[[Automobile]] tires have numerous rating systems.

New automotive tires now also have ratings for traction, treadwear, and temperature resistance (collectively known as [http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=48 UTQG] ratings); as well as speed and load [http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=35 ratings].

Some tread designs are unidirectional and the tire has a rotation direction indicated by an arrow showing which way the tire should rotate when the vehicle is moving forwards. It is important not to put a 'clockwise' tire on the left hand side of the car or a 'counter-clockwise' tire on the right side. [[Tire rotation]] moves tires between the different wheels of the vehicle as front and back [[axle]]s carry different loads and thus the tires wear differently.

'''Tire tread gauges''' are small rulers designed to be inserted into tire treads to measure the remaining tread depth. Local legislation may specify minimum tread depths, typically between 1/8" (3.2 mm) and 1/32" (0.8 mm). '''Wearbars''' may be designed into the tire tread to indicate when it is time to replace the tire. Essentially, part of the tire tread is shallower than the rest and will show when the tire is worn down to that level.

There is currently an attempt to reinforce the tire with nanomaterial. This is likely to increase the tire life, but may turn out to be a bad idea if the worn out part of nanocarbon deposited on the roads is washed off and ends up in the food chain.

====Types of [[automobile]] tires====
* Performance (and racing) tires
** Performance tires tend to be designed for use at higher speeds. They often have a softer rubber compound for improved traction, especially on high speed cornering. The trade off of this softer rubber is a lower treadwear rating.
** Performance street tires sometimes sacrifice wet weather handling by having shallower water channels to provide more actual rubber treat surface area for dry weather performance; the ability to provide both high levels of performance on both wet and dry pavement varies widely between manufacturer and even tire models of the same manufacturer, and is a highly active area for research and development, as well as marketing.
** The ultimate variant of performance tire has no tread pattern at all and is called a slick tire. Slick tires are not legal for use on public roads in most jurisdictions due to their extremely poor wet weather characteristics, but cheater slicks which circumvent the literal wording of the law, if not the intent, are available.
** R compound tires, similar to cheater slicks, are technically approved by the DOT as street legal, but are in fact designed for racing, with minimal tread and ultrasoft rubber. They can typically be distinguished by very low treadwear rating.
** The highest performance tires actually designed to be driven on the street are often called summer or three-season tires, since they are optimized for ultimate warm weather wet and dry performance at the expense of snow and ice traction; they therefore must be replaced with winter or all-season tires, if the vehicle is to be driven much in the winter.
[[Image:Bicycle_winter_tire.jpg|thumb|right|Bicycle winter tire.]]
* Winter (snow and ice) tires
** Winter tires are designed to provide improved performance under winter conditions compared to tires made for use in summer. The rubber compound used in the tread of the tire is usually softer than that used in tires for summer conditions, so providing better grip on ice and snow, but wearing more quickly at higher temperatures. Winter tires often have fine grooves and siping in the tread patterns that are designed to grip any unevenness on ice. Winter tires are usually removed for storage in the spring, because the rubber compound becomes too soft in warm weather resulting in a reduced tire life.
** According to [[California Vehicle Code]] Section 558, "A 'Snow-tread tire' is a tire which has a relatively deep and aggressive tread pattern compared with conventional passenger tread pattern".
** 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, M+S, M&S, or the words MUD AND SNOW (but see All-season tires, below)
** Many winter tires are designed to be studded for additional traction on icy roads. The studs also roughen the ice, so providing better friction between the ice and the soft rubber in winter tires. Use of studs is regulated in most countries, and even prohibited in some countries due to the increased road wear caused by studs.
** Other winter tires rely on factors other than studding for traction on ice, ''e.g.'' highly porous or hydrophilic rubber which adheres to the wet film on the ice surface.
**Some jurisdictions may from time to time require snow tires or traction aids (''e.g.'' tire chains) on vehicles driven in certain areas during extreme conditions.
* All-season tires
** These are an attempt to make a tire that will be a compromise between a tire developed for use on dry and wet roads during summer, and a tire developed for use under winter conditions, when there is snow and ice on the road. However, 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 therefore a compromise, and is neither an excellent summer tire, nor an excellent winter tire. They have, however, become almost ubiquitous as original and replacement equipment on automobiles marketed in the United States, due to their convenience and their adequate performance in most situations.
** All-Season tires are also marked for mud and snow (''e.g.'' M+S, M&S, etc.) the same as winter tires. However, due to the compromise with performance during summer, winter performance is usually not comparable with a winter tire.
* [[Run flat tires]]
* [[All-terrain tyre|All-terrain tires]]
** 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 evacuate mud from the tread.
** Within the all-terrain category, many of the tires available are designed primarily for on-road use, particularly all-terrain tires that are originally sold with the vehicle.
* [[Mud-terrain tyre|Mud tires]]
** Mud terrain tires are characterized by large, chunky tread patterns designed to bite into muddy surfaces and provide grip. The large open design also allows mud to clear more 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 contact patch to prevent the vehicle from sinking too deep into the mud.
** Depending on the composition and tread pattern, many mud terrain tires are not well suited to on-road use. They can be noisy at highway speeds, and due to the open tread design, they have less of a contact area with the road, limiting traction. The large lugs on mud tires tend to tear and chip on roads, because they are made from hard rubber compounds that do not bend easily.
** Mud tires are also marked for mud and snow (''e.g.'' M+S, M&S, etc.) the same as winter tires.

===Railway tires===
[[Image:Train_tire.jpg|thumb|300px|Steel tire on a steam locomotive's driving wheel is heated with gas flames to expand and loosen it so it may be removed and replaced.]]

The steel wheels of railway cars are fitted with tires which are themselves usually made of steel.

(Some trains, mostly certain types of metros and people movers, have rubber tires, including some lines of the Paris Métro, the Mexico City Metro, the Caracas Metro, the Montreal Metro, and the Santiago Metro).

As efficient as the rolling of a steel wheel on a steel rail is, wear still takes place - on acceleration, on braking, and on cornering. As well as the simple wearing away of the wheel surface, a wheel that wears begins to deviate from the correct profile. The shape of a train wheel is designed and specified precisely for the best possible riding and cornering characteristics, and too much wear can alter that. Wear can also take place unevenly if wheels lock up under heavy braking, causing flat spots.

Another different form of damage to a train's wheels takes place if violent wheelslip occurs. The friction so caused can heat the wheel (and rail) enough to cause permanent heat damage.

Replacing a whole wheel because of a worn contact surface proves expensive, so the concept of fitting steel tires to train wheels came about. The tire is a hoop of steel that is fitted around the steel or iron wheel. No obvious form of fastening is generally used to attach it. As with wagon wheels, the tire is held by an interference fit - it is made slightly smaller than the wheel on which it is supposed to fit. To fit a tire, it is heated up until it is glowing hot. Railroad workshops generally have special equipment to do so. As the tire heats, it expands, making it big enough to fit around the wheel. After placing it on the wheel, the tire is cooled, and it shrink fits onto the wheel. When cold, friction between the tire and the wheel is such that the tire will not budge even under quite extreme forces.

Removing a tire is done in reverse - the tire is heated while on the wheel until it loosens.

Tires are reasonably thick, up to about an inch thick or more, giving plenty of room to wear. If a tire wears out of shape, or gets flat-spotted, but has a reasonable amount of metal left, it can be turned on a wheel lathe to refinish it, reshaping it to the correct profile.

== Tire manufacturing & maintenance==
See: [[Tire manufacturing]].

===Some tire manufacturing companies ===
*[[Bridgestone]]
**[[Firestone]]
*[[Continental AG|Continental]]
*[[Cooper Tire & Rubber Company|Cooper]]
*[[Dunlop Tires|Dunlop]]
*[[Goodyear Tire and Rubber Company|Goodyear]]
*[[Kelly Springfield Tire and Rubber Company]]
*[[Kumho]]
*[[Michelin]]
*[[MRF Tyres]]
**[[Goodrich Corporation|B.F. Goodrich]]
**[[Uniroyal]]
**[[Pirelli]]
*[[Nokian Tyres]]
*[[Toyo Tire & Rubber Company|Toyo]]
*[[Yokohama Rubber Company|Yokohama]]

=== Maintenance of [[automobile]] tires ===
Friction from moving contact with the road causes the tread on the outer perimeter of the tire to eventually wear away. When the tire tread becomes too shallow, the tire is considered worn out and should be replaced. The same tire rims can usually be used throughout the lifetime of the car. Uneven or accelerated tire wear can be caused by bad wheel alignment. More wear on a tire facing the outside or the inside of a car is often a sign of bad wheel alignment. When the tread is worn away completely and especially when the wear on the outer rubber exposes the reinforcing threads inside them, the tire is said to be ''bald''. A bald tire should be replaced as soon as possible. Sometimes tires with worn tread are ''recapped'', i. e. a new layer of rubber with grooves is bonded onto the outer perimeter of a worn tire. Because this bonding may occasionally come loose on the tire, new tires are superior to recapped tires.

Sometimes a pneumatic tire gets a hole or a leak through which the air inside leaks out resulting in a '''flat tire''', a condition which must be fixed before the car can be driven further safely. A leak may be slow in a few cases, such as is sometimes observed when the seal between the rim and tire edge is not perfect. Many leaks in flat tires, though, are caused by nails, screws, caltrops, broken glass or other sharp objects puncturing the rubber tire wall. If the hole is small and not elongated, the tire can often be repaired by using plugs from a tire repair kit. A leak in a tire can often be found by submerging the tire, pressurized with air, under water to see where air bubbles come out. If submerging a tire underwater is not possible, the leak can be searched for by covering the pressurized tire surface with a soapy solution to see where leaking air forms soap bubbles. A puncturing object, such as a nail or a screw, can be pulled out using pliers. Then a plug coated with a semi-liquid form of rubber can be inserted into the hole with a special tool. The rubber covering the plug solidifies rather quickly, after which the protruding ends of the plug can be cut off, the tire can be refilled with air to the appropriate pressure, and the repaired wheel replaced on the vehicle. Patches covering a hole have been glued or rubber-cemented to the interior surface of a tire also, particularly if a hole is too elongated for a simple plug. Tire repair with such patches requires the tire to be taken off the rim and then remounted after the patch is applied. Sometimes a more serious rupture of the tire material occurs resulting in a ''blowout''. The damaged tire typically must be replaced after that. A leaking valve stem may occasionally be the cause of a leak, necessitating valve stem replacement. This replacement means the tire will have to be taken off the rim and remounted after the valve replacement. Occasionally, other types of damage require replacement of a tire.

Vehicles typically carry a '''spare tire''', already mounted on a rim, to be used in case a flat tire or blowout occurs. These days, most spare tires (sometimes called "doughnuts") for cars are smaller than normal tires (to save on trunk space, gas mileage, and cost) and should not be driven very far before replacement with a full-size tire. Years ago, full-size or conventional spare tires were used. A few modern vehicle models may use conventional spare tires also. Jacks and tire irons for emergency replacement of a flat tire with a spare tire are included when buying a new car. Not included, but sometimes available separately, are hand or foot pumps for filling a tire with air by the vehicle owner. Cans of pressurized "gas" can sometimes be bought separately for convenient emergency refill of a tire.

Alternatively, many modern cars and trucks are equipped with [[run flat tires]] that may be driven with a puncture - or perhaps are even self-repairing for moderate sized holes.

Front tires, especially on front wheel drive vehicles, have a tendency to wear out more quickly than rear tires. Routine maintenance including [[tire rotation]], exchanging the front and rear tires with each other, is often done periodically to even out tire wear. There are simple hand-held [[tire-pressure gauge]]s which can be temporarily attached to the valve stem to check a tire's interior air pressure. Because of slow leaks or changes in weather or other conditions, tire pressure may occasionally have to be adjusted, usually by refilling through the valve stem with some pressurized air which is often available at service stations.

==Other use and recycling==
Used tires, with too much wear to be safe on vehicles or unrepairable punctures, are among the largest and most problematic sources of waste, due to the large volume produced and their durability. Municipal trash haulers will usually not accept them. Most heavily populated areas contain specific dumps where huge piles of literally millions of discarded tires are kept, often in a constant state of legal antagonism with the municipal authorities. Although tires themselves are not considered hazardous waste, these dumps sometimes catch fire and may burn for months before they can finally be extinguished, creating enormous volumes of toxic air pollution, oil, and heavy metals. Some such fires have become Superfund cleanup sites.

Ironically, those same characteristics which make waste tires such a problem also make them one of the most re-used waste materials, as the rubber is very resilient and can be resued in other products; it also yields much energy when burned under controlled conditions.

Retreadded or recapped tires used to be very common, particularly in the trucking industry; the rubber tread of a tire would wear off long before the carcass, consisting of the fabric plies, sidewalls, and beads, was no longer usable, and therefore good carcasses were simply overlaid with another tread and returned to service. Since the tread is attached in the same way as with a new carcass, such a tire is as reliable as a new one; in fact usually more so, since each individual used carcass is inspected, which is not the case when constructing new tires. With the advances in tire technology leading to longer tread life and the changes in the relative economics of raw materials and labor, this is no longer economically advantageous for automobile tires.

While salvaged tires make cheap toys which can be used variously for pets, animals in captivity or human children, ''e.g.'' the ubiquitous "tire swing", they can also be deliberately torn apart to re-use the rubber.
According to the US Environmental Protection Agency, every year Americans discard approximately 290 million automobile and truck used tires. Since 1989, when only 10 percent of scrap tires were recycled or reused, the United States significantly increased its tire reclamation efforts to slightly more than 80 percent. In 2003, tire reclamation looked like this:
* 130 million were used as fuel
* 56 million were recycled or used in civil engineering projects
* 27.5 million were recycled into other products or projects; for example, rubber lumber, stall mats for horses, roof pads, sports mats, shower tiles, truck bed mats, and commercial flooring
* 12 million were ground up and used in rubber-modified asphalt for roads and athletic tracks
* 9 million were sent to other countries, where they are used to make retreads
In addition to the 290 million scrap tires, 16.5 million used tires in the US are given new temporary life as retreads.

Because of safety issues, new tires must be manufactured primarily from virgin rubber, however, with recycled rubber making up only 5 to 15 percent of the finished product.

Furthermore tire strips are used as a severe instrument for punitive flagellation, which leaves dark bruises.

Mulches made from old tires have become available on the market for individual or industrial agricultural or horticultural use, either as loose pieces mimicking shredded wood, or in sheets of such pieces loosely adhered, for use as walkways, edging, tree rings, stepping stones. Both types of product are also marketed as excellent ground material for playgrounds, being longer lasting and more forgiving that the usual materials used, ''e.g.'' sand, gravel, or shredded wood or bark. Although the materials are extremely resistant to environmental breakdown and essentially last forever, the possibility of whether toxic agents, especially heavy metals, do leach out and possibly contaminate soil, particularly where food crops are grown, is currently under investigation.

==Photos==
<gallery>
Image:107975706c3761 02 runflat.jpg|Run-Flat Tire
</gallery>

==See also==
* [[Slick tire]]
* [[All-terrain tyre|All-terrain tire]]
* [[Mud-terrain tyre|Mud-terrain tire]]
* [[Run-flat tire]]
* [[Whitewall tire]]
* [[Tweel]], a similar technology to the Run-flat tire but created by the [[Michelin]] corporation and a different design.
* [[DUKW]] "The DUKW was the first vehicle which allowed the driver to inflate and deflate the tires from inside the cab, fully inflated for hard surfaces like roads and less inflated for softer surfaces - especially beach sand."
* [[Tire load sensitivity]]
* [[Wheel]]
** [[Custom wheels]]
** [[Magnetic levitation]]

==Sources and References - External Links==
*[http://www.tiresociety.org/ The Tire Society]
*[http://dmoz.org/Shopping/Vehicles/Parts_and_Accessories/Wheels_and_Tires/ DMOZ Wheels and Tires]
*[http://www.rma.org/scrap_tires/scrap_tire_markets/scrap_tire_characteristics/ Rubber Manufacturers Association tire composition]
*[http://www.charityguide.org/volunteer/fewhours/used-tires.htm Used Tires: Reuse, Recycle, Retread]
*[http://www.carbibles.com/tyre_bible.html The Wheel and Tyre Bible]
*[http://www.mearns.org.uk/stonehaven/thomson.htm Robert William Thomson - Pneumatic Tire Inventor]
*[http://www.stausaonline.com/tire-manufacturing/process.html Bias Ply Tire Manufacturing Process]
*[http://www.dot.ca.gov/hq/roadinfo/chcontrl.htm Caltrans' Tire Chain Policies]
*[http://www.epa.gov/osw/conserve/materials/tires/ Management of Scrap Tires]
*[http://www.tacomaworld.com/forum/tirecalc.php Tire Size Calculator]
*[http://www.mudtyres.co.uk Mud Tyres]

[[Category:Auto parts]]
[[Category:Automobiles]]

Car Insurance

2009-09-04T16:40:37Z

Doggyowner:

[[Image:Totaled_jeep_whoa.jpg|frame|right|An insurance company may declare a vehicle totally destroyed ('totaled' or 'a write-off') if it appears replacement would be cheaper than repair. (Photo used with kind permission of [http://www.car-accidents.com car-accidents.com].)]]
'''Vehicle insurance''' (or '''Auto insurance''', '''car insurance''', '''motor insurance''') is insurance consumers can purchase for cars, [[Trucks|trucks]], and other vehicles. Its primary use is to provide protection against losses incurred as a result of [[Car accidents|Motor-vehicle collision]].

==Coverage Levels==
Insurance can cover some or all of the following items:
# The insured party
# The insured vehicle
# Third parties

Different policies specify the circumstances under which each item is covered. For example, a vehicle can be insured against theft, fire damage, or accident damage independently.

==Public Policy==
In many countries it is compulsory to purchase auto insurance before driving on public roads. In the United States, penalties for not purchasing auto insurance vary by state, but often involve a substantial fine, license and/or registration suspension or revocation, as well as possible jail time in some states. Usually the minimum required by law is third party insurance to protect third parties against the financial consequences of loss, damage or injury caused by a vehicle. Typically, coverage against loss of or damage to the driver's own vehicle is optional - one notable exception to this is in Saskatchewan, where Saskatchewan Government Insurance provides collision coverage (less a $700 [[deductible]]) as part of its basic insurance policy. In South Australia Third Party Personal insurance from the State Government Insurance Corporation (SGIC) is included in the license registration fee. South Africa allocates a percentage of the money from petrol into the Road Accidents Fund, which goes towards compensating third parties in accidents.<ref>{{cite web | title = Petrol Structure | url = http://www.dme.gov.za/energy/petrol_structure.htm | format = HTML | publisher = Department of Minerals and Energy, South Africa | accessdate = 2006-05-11}}</ref> Most countries relate insurance to both the car and the driver, however the degree of each varies greatly.

==Basis of Premium Charges==
Depending on the jurisdiction, the insurance premium can be either mandated by the government or determined by the insurance company in accordance to a framework of regulations set by the government. Often, the insurer will have more freedom to set the price on physical damage coverages than on mandatory liability coverages.

When the premium is not mandated by the government, it is usually derived from the calculations of an actuary based on statistical data. The premium can vary depending on many factors that are believed to have an impact on the expected cost of future [[insurance_claim|claims]].<ref>{{cite web | title = Ratemaking | url = http://www.casact.org/admissions/syllabus/ch3.pdf | format = PDF | last = McClenahan | first = Charles | publisher = Casualty Actuarial Society | accessdate = 2006-05-11}}</ref> Those factors can include the car characteristics, the coverage selected ([[deductible]], limit, covered perils), the profile of the driver (age, gender, driving history) and the usage of the car (commute to work or not, predicted annual distance driven).<ref>{{cite web | title = What determines the price of my policy? | url = http://www.iii.org/individuals/auto/b/whatdetermines/ | format = HTML | | publisher = Insurance Information Institute | accessdate = 2006-05-11}}</ref><ref>{{cite web | title = How Are Auto Insurance Rates Calculated? | url = http://insurance.countrywide.com/auto/ratescalculated.aspx | format = HTML | publisher = Countrywide Insurance Services | accessdate = 2006-05-11}}</ref>

===Gender===
Several insurance companies offer a lower premium to female operators as a proxy odometer for lower average mileage. However, most adult rates are unisex.

===Distance===
Some car insurance plans do not differentiate in regard to how much the car is used. However, methods of differentiation would include:

====Reasonable estimation====
Several car insurance plans rely on a reasonable estimation of the average annual distance expected to be driven which is provided by the insured. This discount benefits drivers who drive their cars infrequently but has no actuarial value since it is unverified.

====Odometer-based systems====
Cents Per Mile Now<ref>{{cite web | title = Cents Per Mile Now | url = http://www.centspermilenow.org/ |format = HTML | accessdate = 2006-05-11}}</ref>(1986) advocates classified odometer-mile rates. After the company's risk factors have been applied and the customer has accepted the per-mile rate offered, customers buy prepaid miles of insurance protection as needed, like buying gallons of gasoline. Insurance automatically ends when the odometer limit (recorded on the car’s insurance ID card) is reached unless more miles are bought. Customers keep track of miles on their own odometer to know when to buy more. The company does no after-the-fact billing of the customer, and the customer doesn't have to estimate a "future annual mileage" figure for the company to obtain a discount. In the event of a traffic stop, an officer could easily verify that the insurance is current by comparing the figure on the insurance card to that on the odometer.

Critics point out the possibility of cheating the system by odometer tampering. Although the newer electronic odometers are difficult to roll back, they can still be defeated by disconnecting the odometer wires and reconnecting them later. However, as the Cents Per Mile Now website points out: "As a practical matter, resetting odometers requires equipment plus expertise that makes stealing insurance risky and uneconomical. For example, in order to steal 20,000 miles of continuous protection while paying for only the 2,000 miles from 35,000 miles to 37,000 miles on the odometer, the resetting would have to be done at least nine times to keep the odometer reading within the narrow 2,000-mile covered range. There are also powerful legal deterrents to this way of stealing insurance protection. Odometers have always served as the measuring device for resale value, rental and leasing charges, warranty limits, mechanical breakdown insurance, and cents-per-mile tax deductions or reimbursements for business or government travel. Odometer tampering—detected during claim processing—voids the insurance and, under decades-old state and federal law, is punishable by heavy fines and jail."

Under the cents-per-mile system, rewards for driving less are delivered automatically without need for administratively cumbersome and costly technology. Uniform per-mile exposure measurement for the first time provides the basis for statistically valid rate classes. Insurer premium income automatically keeps pace with increases or decreases in driving activity, cutting back on resulting insurer demand for rate increases and preventing today's windfalls to insurers when decreased driving activity lowers costs but not premiums.

====[[Navigation System|GPS]]-Based System====
In 1998, [[Progressive Corporation|Progressive Insurance]] started a pilot program in Texas in which volunteers installed a [[Global Positioning System|GPS]]-based technology called Autograph in exchange for a discount. The device tracked their driving behavior and reported the results via cellular phone to the company.<ref>{{cite web | title = Progressive's "pay-as-you-drive" auto insurance poised for wide rollout | url = http://info.insure.com/auto/progressive700.html | format = HTML | publisher = insure.com | accessdate = 2006-05-11}}</ref> Policyholders were reportedly more upset about having to pay for the expensive device than they were over privacy concerns.<ref>{{cite web | title = Insurance program rewards drivers who drive less and slower | url = http://www.aftermarketbusiness.com/aftermarketbusiness/article/articleDetail.jsp?id=124842 | format = HTML | publisher = Aftermarket Business | accessdate = 2006-05-11}}</ref>

In 1996, [[Progressive Corporation|Progressive]] filed for and obtained a US patent (US patent 5,797,134) on their process. Progressive has also filed corresponding patent applications in Europe and Japan. UK auto insurer, Norwich Union, has obtained an exclusive license to Progressive's European patent application. They have recently completed a successful pilot test of the technology and it is now available commercially under the tradename "Pay As You Drive™"<ref>{{cite web | title = Pay As You Drive™ Insurance | url = http://www.norwichunion.com/pay-as-you-drive/ | format = HTML | publisher = Norwich Union | accessdate = 2006-05-11}}</ref>

====OBDII-Based System====
In 2004, [[Progressive Corporation|Progressive]] launched another pilot program to allow policyholders to earn a discount on their premiums by consenting to use its [[TripSense]] device. [[TripSense]] connects to a car's OnBoard Diagnostic(OBD-II) port, which exists in all cars built after 1996. The discount is forfeited if the device is disconnected for a significant amount of time.<ref>{{cite web | title = New technology provides detailed info on driving habits | url = http://news.minnesota.publicradio.org/features/2004/08/23_scheckt_autochip/ | format = HTML | publisher = Minnesota Public Radio® | accessdate = 2006-05-11}}</ref>

==Auto Insurance in the United States==

===Coverage Available===
By buying auto insurance, depending on the type of coverage purchased, the consumer may be protected with different coverage types.<ref>{{cite web | title = Coverage Definitions | url = http://www.carinsurance.com/CoverageDefinitions.aspx | format = HTML | publisher = CarInsurance.com | accessdate = 2006-05-11}}</ref>

Due to the sharp decline in value immediately following purchase, there is generally a period in which the remaining car payments exceed the compensation the insurer will pay for a "totaled" (destroyed, or written-off) vehicle. So-called ''GAP insurance''<ref>{{cite web | title = What is GAP insurance? | url = http://www.carinsurance.com/kb/content10049.aspx | format = HTML | publisher = carinsurance.com | accessdate = 2006-05-11}}</ref> was established in the early 1980's to provide protection to consumers based upon buying and market trends. The escalating price of cars, extended term auto loans, and the increasing popularity of leasing gave birth to GAP protection. GAP waivers provide protection for consumers when a "gap" exists between the actual value of their vehicle and the amount of money owed to the bank or leasing company. In some countries including New Zealand and Australia market structures mean that people are more likely to buy a nearly new car than a new car so this is less of a problem.

In the United States, liability insurance covers claims against the policy holder and generally, any other operator of the insured’s vehicle, provided they do not live at the same address as the policy holder and are not specifically excluded on the policy. In the case of those living at the same address, they must specifically be covered on the policy. Thus it is necessary for example, when a family member comes of driving age they must be added on to the policy. Liability insurance generally does not protect the policy holder if they operate any vehicles other than their own. When you drive a vehicle owned by another party, you are covered under that party’s policy. Non-owners policies may be offered that would cover an insured on any vehicle they drive. This coverage is available only to those who do not own their own vehicle and is sometimes required by the government for drivers who have previously been found at fault in an accident.

Generally, liability coverage does extend when you rent a car. However, in most cases only liability applies. Any additional coverage, such as comprehensive policies, i.e. “full coverage” may not apply. Full coverage premiums are based on, among other factors, the value of the insured’s vehicle. This coverage ''may'' not apply to rental cars because the insurance company does not want to assume responsibility for a claim greater than the value of the insured’s vehicle, assuming that a rental car may be worth more than the insured’s vehicle. Most rental car companies offer insurance to cover damage to the rental vehicle. These policies may be unnecessary for many customers as credit card companies, such as Visa and MasterCard, now provide supplemental collision damage coverage to rental cars if the transaction is processed using one of their cards. These benefits are restrictive in terms of the types of vehicles covered.<ref>{{cite web | title = Auto Rental Collision Damage Waiver Program Personal | url = http://usa.visa.com/personal/cards/benefits/bft_dmg_waiver_personal.html | format = HTML | publisher = Visa USA | accessdate = 2006-05-11 }}</ref>

In some regions, the costs associated with not having access to the vehicle ("Loss of Use") is also covered. This is usually an optional coverage.

==United Kingdom Laws regarding Motor Insurance==
In 1930 the UK government introduced a law that required every person who used a vehicle on the road to have at least third party personal injury insurance. Today UK law is defined by the The Road Traffic Act which was last modified in 1991.

The Act requires all motorists to be insured against their liability for injuries to others (including passengers) and for damage to other persons property resulting from use of a vehicle on a public road or in other public places. This is called Third Party Insurance. It is an offence to drive your car, or allow others to drive it, without at least Third Party insurance.

The insurance certificate or cover note issued by the insurance company constitutes legal evidence that the vehicle specified on the document is indeed insured. The Law says that an authorised person, such as the police, may require a driver to produce an insurance certificate for inspection. If the driver cannot show the document immediately on request, then the driver will usually be issued a HORT/1 with seven days, as of midnight of the date of issue, to take a valid insurance certificate (and usually other driving documents as well) to a police station of the driver's choice. Failure to produce an insurance certificate is an offence.

Insurance is more expensive in Northern Ireland than in other parts of the UK.

Motorists in the UK are required to display a Vehicle excise duty disc in their car when it is kept or driven on public roads. This helps to ensure that most people have adequate insurance on their vehicles because you are required to produce an insurance certificate when you purchase the disc. However it is a known practice for some people to purchase insurance to gain the certificate and then to cancel the insurance and gain a full refund within the statutory 14 cooling off period.

==See Also==
* [[Alcohol exclusion laws]]
* [[Extended coverage]]
* [[No fault insurance]]

==Sources==

* [http://www.centspermilenow.org/ Cents Per Mile Now], 2004.
* [http://www.findcheapestinsurance.com/ Compare Car Insurance Quotes] Compare car insurance rates from multiple companies for free; find the cheapest insurance for your car
* [http://www.autotraderleaseguide.com/ Auto Leasing] Consumer-oriented information on auto leasing, how to swap a lease and lease insurance.
* [http://news.minnesota.publicradio.org/features/2004/08/23_scheckt_autochip/ New technology provides detailed info on driving habits], by Tom Scheck, Minnesota Public Radio, August 23, 2004.
* [http://www.carinsurancequotesonline.co.uk/ Guide to Comparing Car Insurance Quotes Online]

[[Category:Car Safety]]
[[Category:Insurance]]