Wire wheel

Wire wheels, wire-spoked wheels, tension-spoked wheels, or "suspension" wheels are wheels whose rims connect to their hubs by wire spokes. Although these wires are generally stiffer than a typical wire rope, they function mechanically the same as tensioned flexible wires, keeping the rim true while supporting applied loads. The term suspension wheel should not be confused with vehicle suspension. Wire wheels are used on most bicycles and are still used on many motorcycles. They were invented by aeronautical engineer George Cayley in 1808. Although Cayley first proposed wire wheels, he did not apply for a patent. The first patent for wire wheels was issued to Theodore Jones of London, England on October 11, 1826. Eugène Meyer of Paris, France was the first person to receive, in 1869, a patent for wire wheels on bicycles. Bicycle wheels were not strong enough for cars until the development of tangentially spoked wheels. They rapidly became well established in the bicycle and motor tricycle world but were not common on cars until around 1907. This was encouraged by the Rudge-Whitworth patented detachable and interchangeable wheels designed by John Pugh. These wheels owed their resistance to braking and accelerative stresses to their two inner rows of tangential spokes. An outer row of radial spokes gave lateral strength against cornering strains. These wheels were deeply dished so that steering pivot pins might lie as near as possible to the center-line of the tires. Their second feature was that they were easily detachable being mounted on splined false hubs. A process of assembling wire wheels is described as wheelbuilding. Wire wheels on a 1929 Alfa Romeo 6C 1750 Spyder Supersport Rudge-Whitworth wire wheel on a 1922 Vauxhall 25 Wire wheels on a 1957 MGA On automobile From the earliest days automobiles used either wire wheels or heavy wooden or pressed steel spoked artillery type. The development of the quick detachable hubs of either Rudge-Whitworth or Riley design did much to popularise wire wheels and incidentally led to the fitting of "spare wheels". After their wooden spoked artillery wheels proved inadequate many US manufacturers paid John Pugh of Rudge-Whitworthroyalties to manufacture wire wheels using his patents. Artillery wheels fell out of favour in the late 1920s and the development of the cheaper pressed steel wheels by Joseph Sankey replaced wire wheels wherever the premium price of wire wheels was not justified by their weight saving. A sample of cars first riding on wire wheels Cadillac Chrysler Ford Lincoln Packard Rolls-Royce Phantom III 1937 high-quality centre-lock (wire) wheels streamlined by nave plates Sports cars Before 1960, sports/racing cars usually had Rudge-Whitworth wire wheels center-locking equipped with splined hubs and a quick-release "knockoff" (central wing nut) locking cap that could be unscrewed by striking a wing...

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Rim (wheel)

The rim is the "outer edge of a wheel, holding the tire". It makes up the outer circular design of the wheel on which the inside edge of the tire is mounted on vehicles such as automobiles. For example, on a bicycle wheel the rim is a large hoop attached to the outer ends of the spokes of the wheel that holds the tire and tube. The term rim is also used non-technically to refer to the entire wheel, or even to a tire. In the 1st millennium BC, an iron rim was introduced around the wooden wheels of chariots. Cross section of a bicycle rim wooden bicycle rim with tubular tyre Characteristics Scratched rim on two-piece wheel. Black residue remaining from where the tire was seated on the "safety profile" rim. Diameter (effective): distance between the bead seats (for the tire), as measured in the plane of the rim and through the axis of the hub which is or will be attached, or which is integral with the rim. Width (effective): separation distance between opposed rim flanges. The flange-to-flange width of a rim should be a minimum of three-quarters of the tire section width. And the maximum rim width should be equal to the width of the tire tread. Type: Depends on the type of vehicle and tire. There are various rim profiles, as well as the number of rim components.   Thomas B. Jeffery's 1882 clincher rim patent Modern passenger vehicles and tubeless tires typically use one-piece rims with a "safety" rim profile. The safety feature helps keep the tire bead held to the rim under adverse conditions by having a pair of safety humps extending inwardly of the rim toward the other tire bead seat from an outer contoured surface of the rim. Heavy vehicles and some trucks may have a removable multi-piece rim assembly consisting of a base that mounts to the wheel and axle. They then have either a side ring or a side and lock ring combination. These parts are removable from one side for tire mounting, while the opposite side attached to the base has a fixed flange. Material: Various metals can be used for the rim. Commonly seen are alloy (magnesium and aluminum), mag (magnesium), aluminum, and chrome. Teflon coatings are sometimes also applied for an extra layer of protection. Vehicle performance: Because the rim is where the tire resides on the wheel and the rim supports the tire shape, the dimensions of the rims are a factor in the handling characteristics of an automobile. For example: Overly wide rims in relation...

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Direct TPMS

Direct TPMS, or direct tire pressure monitoring systems (direct sensor TPMS) refers to the use of a pressure sensor directly mounted on the wheels or tires of a vehicle. The pressure inside the tire is measured using a pressure transducer with the pressure information being subsequently sent to the vehicle to warn the driver of under or over inflation of a tire. The pressure information is commonly transmitted to the vehicle using radio frequency (RF) technology, though systems using mechanical, electrical or magnetic methods have been used over recent years. Typical system direct TPM sensor fitted in valve system, manufacturer VDO In most current designs of direct TPMS, a small electronic assembly which is rugged enough to be mounted inside a tire, measures the pressure using a microelectromechanical system (MEMS) pressure sensor and then transmits this and other information to one or more vehicle receivers. Other information can include a serial number, temperature, acceleration and the status of the complete tire pressure monitoring system. The purpose of the serial number is to allow the vehicle to ignore transmissions from other vehicles and operate with a unique data field. A typical direct TPMS (e.g. Ford, BMW or Toyota) comprises the following components on a vehicle: A direct TPM sensor fitted to the back of the valve stem on each wheel A TPM Warning Light Unique identifier (ID's) for which tire is providing the data including speed and the direction of rotation A tire pressure monitor electronic control unit (ECU) Antenna(s) Controller for periodic measurements Source of power Diagnostics and wake up system Most direct TPMS systems use ultra high frequency (UHF) radio in one of the 'unlicensed' ISM bands (industrial, scientific and medical) for transmitting the data, often around 434 MHz in Europe and 315 MHz in much of the rest of the world. On some systems there is a separate receiver or antenna near each wheel whilst more commonly there is a single receiver which receives data from all of the wheels on the vehicle. Commonly this receiver is also used for remote keyless entry system (RKE) as this also usually uses UHF radio transmissions. TPM sensors can be fitted to the wheels in a number of ways. They can be mounted on the back of the tire's valve stem or attached using adhesive or to a band which is then securely wrapped around the rim inside the tire, usually in the drop zone. Direct tire pressure monitor system warning light When the direct TPMS warning light comes on, either one of the tires is under-inflated, severely over-inflated, or there is a fault with the system. If the light is constant then inflating to the correct placard pressure should turn it off. If this is not the case then this indicates a puncture. If...

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Tire-pressure gauge

A tire-pressure gauge, or tyre-pressure gauge, is a pressure gauge used to measure the pressure of tires on a vehicle. Since tires are rated for specific loads at certain pressure, it is important to keep the pressure of the tire at the optimal amount. Tires are rated for their optimal pressure when cold, meaning before the tire has been driven on for the day and allowed to heat up, which ultimately changes the internal pressure of the tire due to the expansion of gases. The precision of a typical mechanical gauge as shown is ±3 psi (21 kPa). Higher precision gauges with ±1 psi (6.9 kPa) uncertainty can also be obtained. A tire-pressure gauge in use. The example in this image is a Bourdon tube gauge. Built-in tire pressure sensors Many modern cars now come with built-in tire pressure sensors that allow all four tire pressures to be read simultaneously from inside the car. In 2005, most on-board Tire Pressure Monitoring Systems (TPMS) used indirect pressure monitoring. The anti-lock brake sensors detect one tire rotating faster than the rest and indicate a low tire pressure to the driver. The problem with this method was that if tires all lost the same pressure then none would show up against the others to indicate a problem. Regulations on tire pressure Since September 2007 all new automobiles below 10,000 lb (4,500 kg) in weight sold in the United States are required to incorporate a Tire Pressure Monitoring System, which is capable of monitoring all four tires and simultaneously reporting under-inflation of 25 percent of cold placard pressures in any combination of all four tires. TPMS known as Direct TPMS are capable of TREAD Act legislation requiring simultaneous pressure measurement for each tire pressure. Early TPMS sensors required batteries, but the latest TPMS technology eliminates all sensor batteries. References http://www.nhtsa.dot.gov/cars/testing/ncap/Tyres/pages/TPandLoading.htm http://etv.com.au

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Central tire inflation system

A central tire inflation system (CTIS) is a system to provide control over the air pressure in each tire of a vehicle as a way to improve performance on different surfaces. For example, lowering the air pressure in a tire creates a larger area of contact between the tire and the ground and makes driving on softer ground much easier. It also does less damage to the surface. This is important on work sites and in agricultural fields. By giving the driver direct control over the air pressure in each tire, maneuverability is greatly improved. Another function of the CTIS is to maintain pressure in the tires if there is a slow leak or puncture. In this case, the system controls inflation automatically based on the selected pressure the driver has set. Tractor-drawn trailer with CTIS Tatra T813 prototype had CTIS already in 1960, it later became standard for all Tatra military trucks CTIS is extensively used in many off-road transport operations. In many countries, especially Australia, New Zealand and South Africa, CTIS is used in logging, in mining, and in power line maintenance. CTIS significantly reduces environmental impact when transporting logs, or travelling on gravel or dirt roads. Benefits include ironing out ruts and previous road damage, like washboards or corrugations. Reducing the tire pressure also reduces the grinding action on the gravel, significantly reducing dust and silt. CTIS also extends truck, tire, and drive train life, by significantly reducing vibration and shock loading. Feedback from Australian logging contractors show a doubling of transmission and differential life. Tire life can double, with drive tire life increasing from 27,000 km to 45,000 regularly shown . Even in flatter areas, drive tire life increased from 90,000 to 135,000 . There have been attempts at employing central tire inflation system on aircraft landing wheels (notably on the Soviet Antonov An-22 military transport) to improve their preparedness for unpaved runways. Use CTIS was first used in production on the American DUKW amphibious truck which was introduced in 1942. The Czech heavy military 8x8 truck Tatra T813's central inflation and deflation system was designed to maintain pressure even after multiple bullet punctures. Military Tatra trucks are equipped with CTIS as standard. From 1984, GM offered CTIS for the Chevrolet Blazer and various pick-ups. Several trucks used by the U.S. military also have CTIS (e.g. the HMMWV and its civilian counterpart, the Hummer H1). The feature is also common in Soviet and Russian military trucks. References  "Central tire inflation system". Retrieved 2010-05-13.

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Magnesium wheels

Magnesium wheels are wheels manufactured from alloys which contain mostly magnesium. Magnesium wheels are produced either by casting (metalworking) (where molten metal is introduced into a mold, solidifying within the mold), or by forging (where a prefabricated bar is deformed mechanically). Magnesium has several key properties that make it an attractive base metal for wheels: lightness; a high damping capacity; and a high specific strength. Magnesium is the lightest metallic structural material available. It is 1.5 times less dense than aluminium, so magnesium wheels can be designed to be significantly lighter than aluminium alloy wheels, while exhibiting comparable strength. All competitive racing rims are now made of magnesium alloy. Cast magnesium wheels Taking into account their generally inferior quality compared to forged wheels, the main advantage of cast wheels is the relatively low cost of production. And although cast wheels are more affordable than forged wheels, cast wheels are heavier than forged wheels for a given required load. Manufacturing defects found in cast wheels include cavities or porosity and a different metallurgical microstructure, entailing larger grain size. Cast wheels will tend to fracture upon overbearing high-speed impact, whereas forged wheels will tend to bend. Forged magnesium wheels Forged magnesium wheels are manufactured by mechanically deforming (forging) a prefabricated rod using a powerful forging press. Several somewhat different forging techniques exist, all of them comprising a multi-step process/operation. The resultant forging is subsequently machined (lathe-turned and milled) into the final shape of a wheel by removing excess metal from the forged blank. A forged magnesium wheel is 25 percent lighter than cast wheel. The main disadvantage of forged wheels is the high manufacturing cost. And due to the typically high costs of finished wheels, forged wheels are still rarely purchased by non-professional drivers for regular road use. But since forged wheels can be designed to be lighter than cast wheels for a given load, forged wheels do offer fuel economy and other distinct advantages. The forging process allows alignment of the metal fibers and optimization of the directional pattern arrangement along the spokes of a wheel. This, along with the smaller grain size, results in superior mechanical properties and performance characteristics that make forged magnesium wheels widely popular both for motor racing and with knowledgeable driving enthusiasts. History The original cast magnesium wheels were made beginning in the 1930s and their production continues today. Some of the biggest brands producing magnesium wheels in the past include Halibrand, American Racing, Campagnolo, Cromodora, Ronal, Technomagnesio, and Watanabe. The popularity of magnesium...

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Uniform Tire Quality Grading

Uniform Tire Quality Grading, commonly abbreviated as UTQG, is the term encompassing a set of standards for passenger car tires that measures a tire's treadwear, temperature resistance and traction. The UTQG was created by the National Highway Traffic Safety Administration in 1978, a branch of the United States Department of Transportation (DOT). All tires manufactured for sale in the United States since March 31, 1979 are federally mandated to have the UTQG ratings on their sidewall as part of the DOT approval process, in which non-DOT approved tires are not legal for street use in the United States. It is not to be confused with the tire code, a supplemental and global standard measuring tire dimensions, load-bearing ability and maximum speed, maintained by tire industry trade organizations and the International Organization for Standardization. The National Highway Traffic Safety Administration (NHTSA) established the Uniform Tire Quality Grading Standards (UTQGS) in 49 CFR 575.104. When looking at UTQG ratings it is important to realize that the Department of Transportation does not conduct the tests. The grades are assigned by the tire manufacturers based on their test results or those conducted by an independent testing company they have hired. The NHTSA has the right to inspect the tire manufacturer's data and can fine them if inconsistencies are found.  Dedicated winter tires, also known as snow tires, are not required to have a UTQG rating. Non-passenger car tires, such as those for motorcycles, buses, medium trucks and above along with trailers are also not required to have a UTQG rating, although FMVSS Standard 109 requires the following to be listed on the tire's sidewall: speed restriction if less than 55 mph, regroovable if designed for regrooving, and a letter designating load range rating. UTQG ratings (top) and tire code(bottom) on sidewall of Continental ContiProContact tire Components The UTQG rating is made up of three components, treadwear, traction and temperature. Treadwear The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test track. A tire graded 200 would last twice as long on the government test course under specified test conditions as one graded 100. In theory, this means that a tire with a 200 grade will wear twice as long as a tire with a 100 grade. However, tire manufacturers are not under any obligation to grade a tire based on the test results, except to say that they cannot overstate the grade. This is enforced by NHTSA requiring documentation to justify any assignment of a grade on a tire, "These treadwear grades are no...

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