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Wikipedia

Run-flat tire

January 07, 2023

A run-flat tire/tyre is a pneumatic vehicle tire that is designed to resist the effects of deflation when punctured, and to allow the vehicle to continue to be driven at reduced speeds - under 90 km/h (56 mph) – and for limited distances – usually 16 to 80 km (10 to 50 mi), depending on the type of tire.

Cutaway model of MOWAG Piranha tire

Technologies

There are three basic technologies currently available, described below.

Self-supporting

The origins of the commercial self-supporting run-flat tire started in 1935 with a tire that had a fabric inner tire. The tire was advertised as a protection against blowouts, a common and dangerous occurrence in the 1930s.[1]

In 1934, Michelin introduced a tire that was based on technology developed for local commuter trains and trolleys. It had a safety rim inside the tire which if punctured would run on a special foam lining. The tire was sold for military use and for specialized vehicles like bank armoured cars. It was advertised as "semi-bulletproof". While the tire performed as advertised it was far too expensive to be a feasible option for most private automobile users.[2]

In 1958, Chrysler teamed with Goodyear Tire and Rubber Company to offer Captive Air run-flat tires using an interlining to carry the weight.

In 1972 Dunlop launched the Total Mobility Tyre (later Denovo) "fail-safe" wheel and tire system that became optional equipment on the Rover P6 3500 in 1973,[3] and by 1983 evolved into the TD/Denloc which became standard equipment across the whole Austin Metro range.

Most recently, Bridgestone and Pirelli run-flat tires are supplied on some new model BMW cars. The automaker promoted these as a safety feature and as an alternative to carrying a spare tire.

 
Cut-Out View of PZT Tire

Pressure Zero Tire (PZT)[4] was pioneered by American Engineering Group (AEG) for US Special Forces. AEG prototype dissipates heat and has the tire flexibility and strength to support the heavy military pick-up weight while providing a relatively smooth ride. The durability characteristics of this design were studied further on four different tire sizes for ATV Polaris, Toyota Hilux, and Toyota Land Cruiser & GMV 1.1. special operations vehicles.

Self-supporting run-flat tires are now common on light trucks and passenger cars and typically allows the vehicle to be driven for 50 miles (80 km) at around 50 miles per hour (80 km/h). However, if the tires are subject to this kind of misuse, wheels may become damaged in the process, and repair may be impossible or unsafe, especially if the tire is punctured in the sidewall or at the edge of the tread. These tires carry a 20% to 40% weight penalty over similar standard tires and the thicker sidewall also means higher rolling resistance, which reduces the vehicle's fuel economy.[5] However, the weight penalty of the individual tire is usually more than compensated by the fact that the vehicle need no longer carry a spare, as well as the equipment needed to swap in the spare. The thicker sidewall however results in more road imperfections filtering through the tire to the rim and hence to the car, which results in a harsher ride.[6]

Self-sealing

See also: Self-sealing fuel tank

These tires contain an extra lining within the tire that self-seals in the event of a small hole due to a nail or screw. In this way, the loss of air is prevented from the outset such that the tire is either permanently self-repairing or at least loses air very slowly.

There are also a number of retrofitted tire sealants which act in a similar way to self-sealing tires. These compounds are normally injected through the tire valve. The rotating force then distributes the compound onto the inner surface of the tire to act as a self-sealing lining within the tire.

Auxiliary-supported

 
Run-flat tire with support ring

In this system, there is an additional support ring or insert attached to the wheel that can support the weight of the vehicle in the event of a loss of pressure. The run-flat insert has an unsurpassed ability to carry heavy vehicle loads for long distances at high speeds. It is therefore the normal run-flat selection for military vehicles, high-level executive protection vehicles, and "armored" vehicles[7] used by government, aid groups, or private contractors in conflict zones.

Standards of performance

The basic benefit of using run-flat tires is continued mobility in case of a loss of air pressure, due either to a 'normal' puncture or to a hostile deliberate act including a bullet strike while the vehicle is traveling at high speed. Performance criteria are therefore in terms of distance and speed at which the vehicle can escape without becoming immobile and the steering control over the vehicle during this process.

The usual standard of performance, especially for military or security vehicles, are the Finabel standards.[7]

Market share

Run-flat tires accounted for less than 1% of replacement tire sales in the U.S. in 2005. In 2006, it was expected that such tires would gain popularity with armored vehicle manufacturers, but growth figures were slow with one major model, the Michelin PAX System, no longer being developed by the manufacturer (though replacements will be produced for the foreseeable future).[8] A Michelin study released in 2008 found that 3% of drivers worldwide want run-flat tires. U.S. market share is well below 1%. American Honda Motor Co. announced that the 2009 Honda Odyssey Touring and Acura RL were its last models available with run-flat tires and with Honda no longer using run-flats. This leaves only a handful of volume manufacturers offering them as standard fittings and only on some models. An exception is BMW, who are the largest fitter of run-flats as original equipment.[5]

Former US President Barack Obama's presidential limo, "the Beast", had Goodyear Kevlar lined run-flat tires.[9]

Factors contributing to small market share

The cost can be more than double other tires of comparable size. Also, run-flat tires cannot be run flat if the flat is due to sidewall damage, a common cause of flats. Also, under the best circumstances, the speed and range that the run-flat tires can be run flat is very limited. Run-flat tires cannot be driven over 50 miles per hour and usually offer only up to 50 miles of extended mobility. These limitations lower the value of the extra expense for many buyers. In certain applications, depending on the vehicle, specific tire design, and driving surface, a run-flat tire can provide from 25 miles to 200 miles driving while flat with limited speed.

For Goodyear Tire, one effect on market share is the policy to prohibit the repair of tires punctured by nails or other road hazards; while Goodyear tires can be repaired, the manufacturer's warranty and liability is voided.[citation needed]

See also

References

  1. ^ "Fabric Inner Tube Lessens Blowout Hazards". Popular Mechanics. 63 (4): 488. April 1935. from the original on 18 April 2021. Retrieved 10 June 2012.
  2. ^ "Bullet Proof Tire Has Sponge Rubber Tube". Popular Mechanics. 62 (6): 872. December 1934. from the original on 18 April 2021. Retrieved 10 June 2012.
  3. ^ "Evening Times - Google News Archive Search". news.google.com. from the original on 2021-04-18. Retrieved 2020-12-16.
  4. ^ Pressure Zero Tire: American Engineering Group wins award for its zero pressure tire http://www.tractionnews.com/american-engineering-group-wins-award-zero-pressure-tire-technology/ 2019-04-30 at the Wayback Machine
  5. ^ a b Kranz, Rick (27 July 2009). "The air runs out of run-flat tires". The Center for Auto Safety. from the original on 15 September 2011. Retrieved 10 June 2012.
  6. ^ McIntosh, Jil (24 October 2017). "Run-Flats vs Self-Sealing Tires". Autotrader Canada. from the original on 14 February 2019. Retrieved 15 February 2019.
  7. ^ a b Test Operations Procedure (TOP) 02-2-698 Runflat Testing 2021-04-18 at the Wayback Machine.-U.S. Army Test and Evaluation Command. - 2015.
  8. ^ Jensen, Christopher (20 April 2008). "Michelin Giving Up on PAX Run-Flat Tire". The New York Times. from the original on 26 February 2015. Retrieved 2 July 2010.
  9. ^ "The Beast: President Barack Obama's High-Tech Super-Limo". thecarconnection.com. from the original on 2016-04-05. Retrieved 2016-04-18.

January 07, 2023
flat, tire, flat, tire, tyre, pneumatic, vehicle, tire, that, designed, resist, effects, deflation, when, punctured, allow, vehicle, continue, driven, reduced, speeds, under, limited, distances, usually, depending, type, tire, cutaway, model, mowag, piranha, t. A run flat tire tyre is a pneumatic vehicle tire that is designed to resist the effects of deflation when punctured and to allow the vehicle to continue to be driven at reduced speeds under 90 km h 56 mph and for limited distances usually 16 to 80 km 10 to 50 mi depending on the type of tire Cutaway model of MOWAG Piranha tire Contents 1 Technologies 1 1 Self supporting 1 2 Self sealing 1 3 Auxiliary supported 2 Standards of performance 3 Market share 3 1 Factors contributing to small market share 4 See also 5 ReferencesTechnologies EditThere are three basic technologies currently available described below Self supporting Edit The origins of the commercial self supporting run flat tire started in 1935 with a tire that had a fabric inner tire The tire was advertised as a protection against blowouts a common and dangerous occurrence in the 1930s 1 In 1934 Michelin introduced a tire that was based on technology developed for local commuter trains and trolleys It had a safety rim inside the tire which if punctured would run on a special foam lining The tire was sold for military use and for specialized vehicles like bank armoured cars It was advertised as semi bulletproof While the tire performed as advertised it was far too expensive to be a feasible option for most private automobile users 2 In 1958 Chrysler teamed with Goodyear Tire and Rubber Company to offer Captive Air run flat tires using an interlining to carry the weight In 1972 Dunlop launched the Total Mobility Tyre later Denovo fail safe wheel and tire system that became optional equipment on the Rover P6 3500 in 1973 3 and by 1983 evolved into the TD Denloc which became standard equipment across the whole Austin Metro range Most recently Bridgestone and Pirelli run flat tires are supplied on some new model BMW cars The automaker promoted these as a safety feature and as an alternative to carrying a spare tire Cut Out View of PZT Tire Pressure Zero Tire PZT 4 was pioneered by American Engineering Group AEG for US Special Forces AEG prototype dissipates heat and has the tire flexibility and strength to support the heavy military pick up weight while providing a relatively smooth ride The durability characteristics of this design were studied further on four different tire sizes for ATV Polaris Toyota Hilux and Toyota Land Cruiser amp GMV 1 1 special operations vehicles Self supporting run flat tires are now common on light trucks and passenger cars and typically allows the vehicle to be driven for 50 miles 80 km at around 50 miles per hour 80 km h However if the tires are subject to this kind of misuse wheels may become damaged in the process and repair may be impossible or unsafe especially if the tire is punctured in the sidewall or at the edge of the tread These tires carry a 20 to 40 weight penalty over similar standard tires and the thicker sidewall also means higher rolling resistance which reduces the vehicle s fuel economy 5 However the weight penalty of the individual tire is usually more than compensated by the fact that the vehicle need no longer carry a spare as well as the equipment needed to swap in the spare The thicker sidewall however results in more road imperfections filtering through the tire to the rim and hence to the car which results in a harsher ride 6 Self sealing Edit See also Self sealing fuel tank These tires contain an extra lining within the tire that self seals in the event of a small hole due to a nail or screw In this way the loss of air is prevented from the outset such that the tire is either permanently self repairing or at least loses air very slowly There are also a number of retrofitted tire sealants which act in a similar way to self sealing tires These compounds are normally injected through the tire valve The rotating force then distributes the compound onto the inner surface of the tire to act as a self sealing lining within the tire Auxiliary supported Edit Run flat tire with support ring In this system there is an additional support ring or insert attached to the wheel that can support the weight of the vehicle in the event of a loss of pressure The run flat insert has an unsurpassed ability to carry heavy vehicle loads for long distances at high speeds It is therefore the normal run flat selection for military vehicles high level executive protection vehicles and armored vehicles 7 used by government aid groups or private contractors in conflict zones Standards of performance EditThe basic benefit of using run flat tires is continued mobility in case of a loss of air pressure due either to a normal puncture or to a hostile deliberate act including a bullet strike while the vehicle is traveling at high speed Performance criteria are therefore in terms of distance and speed at which the vehicle can escape without becoming immobile and the steering control over the vehicle during this process The usual standard of performance especially for military or security vehicles are the Finabel standards 7 Market share EditRun flat tires accounted for less than 1 of replacement tire sales in the U S in 2005 In 2006 it was expected that such tires would gain popularity with armored vehicle manufacturers but growth figures were slow with one major model the Michelin PAX System no longer being developed by the manufacturer though replacements will be produced for the foreseeable future 8 A Michelin study released in 2008 found that 3 of drivers worldwide want run flat tires U S market share is well below 1 American Honda Motor Co announced that the 2009 Honda Odyssey Touring and Acura RL were its last models available with run flat tires and with Honda no longer using run flats This leaves only a handful of volume manufacturers offering them as standard fittings and only on some models An exception is BMW who are the largest fitter of run flats as original equipment 5 Former US President Barack Obama s presidential limo the Beast had Goodyear Kevlar lined run flat tires 9 Factors contributing to small market share Edit The cost can be more than double other tires of comparable size Also run flat tires cannot be run flat if the flat is due to sidewall damage a common cause of flats Also under the best circumstances the speed and range that the run flat tires can be run flat is very limited Run flat tires cannot be driven over 50 miles per hour and usually offer only up to 50 miles of extended mobility These limitations lower the value of the extra expense for many buyers In certain applications depending on the vehicle specific tire design and driving surface a run flat tire can provide from 25 miles to 200 miles driving while flat with limited speed For Goodyear Tire one effect on market share is the policy to prohibit the repair of tires punctured by nails or other road hazards while Goodyear tires can be repaired the manufacturer s warranty and liability is voided citation needed See also EditAirless tire Direct TPMS Tire manufacturing Tire mousse Tire pressure monitoring system Tweel Michelin s air free tireReferences Edit Fabric Inner Tube Lessens Blowout Hazards Popular Mechanics 63 4 488 April 1935 Archived from the original on 18 April 2021 Retrieved 10 June 2012 Bullet Proof Tire Has Sponge Rubber Tube Popular Mechanics 62 6 872 December 1934 Archived from the original on 18 April 2021 Retrieved 10 June 2012 Evening Times Google News Archive Search news google com Archived from the original on 2021 04 18 Retrieved 2020 12 16 Pressure Zero Tire American Engineering Group wins award for its zero pressure tire http www tractionnews com american engineering group wins award zero pressure tire technology Archived 2019 04 30 at the Wayback Machine a b Kranz Rick 27 July 2009 The air runs out of run flat tires The Center for Auto Safety Archived from the original on 15 September 2011 Retrieved 10 June 2012 McIntosh Jil 24 October 2017 Run Flats vs Self Sealing Tires Autotrader Canada Archived from the original on 14 February 2019 Retrieved 15 February 2019 a b Test Operations Procedure TOP 02 2 698 Runflat Testing Archived 2021 04 18 at the Wayback Machine U S Army Test and Evaluation Command 2015 Jensen Christopher 20 April 2008 Michelin Giving Up on PAX Run Flat Tire The New York Times Archived from the original on 26 February 2015 Retrieved 2 July 2010 The Beast President Barack Obama s High Tech Super Limo thecarconnection com Archived from the original on 2016 04 05 Retrieved 2016 04 18 Retrieved from https en wikipedia org w index php title Run flat tire amp oldid 1112956658, wikipedia, wiki, book, books, library,

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