Airless tire

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12-16.5 Mk1 Croc Tyre with rim center fitted 2005 091112-28rim0051 compressed.JPG
12-16.5 Mk1 Croc Tyre with rim center fitted

Airless tires, non-pneumatic tires (NPT), or flat-free tires are tires that are not supported by air pressure. They can be used on small vehicles such as riding lawn mowers and motorized golf carts. They also are used on heavy equipment required to operate on sites where risk of tire punctures is high. Tires composed of closed-cell polyurethane foam are also made for bicycles and wheelchairs.

Contents

Advantages & disadvantages

The main advantages of airless tires is that they do not go flat and need to be replaced less frequently. Heavy equipment outfitted with airless tires will be able to carry more weight and engage in more rugged activities. [1]

Airless tires generally have higher rolling resistance and provide somewhat less suspension than similarly shaped and sized pneumatic tires. Other problems for airless heavy equipment tires include dissipating the heat buildup that occurs when they are driven. Airless tires are often filled with compressed polymers (plastic) rather than air, or can be a solid molded product.

Airless tires are attractive to cyclists, as bicycle tires are much more vulnerable to punctures than motor vehicle tires.

The drawbacks to airless tires depend on the use. Heavy equipment operators who use machinery with solid tires may become fatigued. Any airless tire will be heavier than the rubber tire it is meant to replace.

However, airless tires are not popular with hardcore off-roaders, as those vehicles often need to travel long distances at highway speeds. At speeds above 80 km/h, they can be unstable, causing severe vibrations (and passenger discomfort), and therefore potential for drivers to lose vehicle control. [2]

Installation of airless tires depends on the use. Heavy equipment will need special equipment to mount, but an airless bicycle tire can be mounted with little effort. Solid airless lawnmower tires come pre-installed on the wheel, allowing quick installation.[ citation needed ]

Examples

An Airless tire fitted on a Mobike Mobike tire - 02.jpg
An Airless tire fitted on a Mobike

Many bicycle-sharing systems use these tires to reduce maintenance.

In 1938, J. V. Martin in the United States invented a safety tire with hoops of hickory encased in rubber and fitted with criss cross spokes of ribbed rubber. It could drive over 100 mm (4 inches) blocks when tested in a springless test car. [3]

In 2005, Michelin started developing an integrated tire and wheel combination, the "Tweel" (derived from "tire" and "wheel," which are combined into one new, fused part), which operates entirely without air. Michelin claims its "Tweel" has load carrying, shock absorbing, and handling characteristics that compare favorably to conventional pneumatic tires. [4] However, the tire has a lot of vibration when driving over 80 km/h (50 mph). Therefore the tire is only available for golf carts, ATV's and skid steer vehicles. In 2019 however Michelin and GM announced their goal of making a new airless tire for passenger vehicles available in 2024. [5] The automotive engineering group of the mechanical engineering department at Clemson University is developing a low energy loss airless tire with Michelin through the NIST ATP project.

Resilient Technologies and the University of Wisconsin–Madison's Polymer Engineering Center are creating a "non-pneumatic tire", which is a round polymeric honeycomb wrapped with a thick, black tread. The initial version of the tire is for the Humvee and is expected to be available in 2012. [6] [7] It is also the first group to make a commercially available mass-produced airless tire after its acquisition by Polaris, [8] albeit only as coupled with their vehicle. The tire trademark is "Terrainarmor".

Bridgestone is developing the Bridgestone Air-Free Concept Tire, which can hold 150 kg (330 lb) per tire. [9]

The Energy return wheel (ERW) has the outer edge of the tire connected to the inner rim by a system of springs. The springs can have their tension changed to vary the handling characteristics. [10]

Hankook Tire is developing the iFlex airless tire. [11]

However, many tire manufacturing companies are yet to start making airless tire due to different limitations. Major companies like Goodyear say its airless tires won't be road-ready until 2030. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Tire</span> Ring-shaped covering that fits around a wheels rim

A tire or tyre is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which the wheel travels. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, which also provide a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, called a contact patch, that is designed to match the weight of the vehicle with the bearing strength of the surface that it rolls over by providing a bearing pressure that will not deform the surface excessively.

<span class="mw-page-title-main">Michelin</span> French multinational tyre manufacturing company

Michelin is a French multinational tyre manufacturing company based in Clermont-Ferrand in the Auvergne-Rhône-Alpes région of France. It is the second largest tyre manufacturer in the world behind Bridgestone and larger than both Goodyear and Continental. In addition to the Michelin brand, it also owns the Kléber tyres company, Uniroyal-Goodrich Tire Company, SASCAR, Bookatable and Camso brands. Michelin is also notable for its Red and Green travel guides, its roadmaps, the Michelin stars that the Red Guide awards to restaurants for their cooking, and for its company mascot Bibendum, colloquially known as the Michelin Man, who is a humanoid consisting of tyres.

<span class="mw-page-title-main">Rubber-tyred metro</span> Form of rapid transit

A rubber-tyred metro or rubber-tired metro is a form of rapid transit system that uses a mix of road and rail technology. The vehicles have wheels with rubber tires that run on rolling pads inside guide bars for traction, as well as traditional railway steel wheels with deep flanges on steel tracks for guidance through conventional switches as well as guidance in case a tyre fails. Most rubber-tyred trains are purpose-built and designed for the system on which they operate. Guided buses are sometimes referred to as 'trams on tyres', and compared to rubber-tyred metros.

<span class="mw-page-title-main">Bridgestone</span> Japanese multinational auto and truck parts manufacturer

Bridgestone Corporation is a Japanese multinational tire manufacturer founded in 1931 by Shojiro Ishibashi (1889–1976) in the city of Kurume, Fukuoka, Japan. The name Bridgestone comes from a calque translation and transposition of ishibashi (石橋), meaning 'stone bridge' in Japanese.

<span class="mw-page-title-main">Racing slick</span> Type of tire used in auto racing

A racing slick or slick tyre is a type of tyre that has a smooth tread used mostly in auto racing. The first production slick tyre was developed by M&H Tires in the early 1950s for use in drag racing. By eliminating any grooves cut into the tread, such tyres provide the largest possible contact patch to the road, and maximize dry traction for any given tyre dimension; see Performance. Slick tyres are used on race tracks and in road racing, where acceleration, steering and braking require maximum traction from each wheel. Slick tyres are typically used on only the driven (powered) wheels in drag racing, where the only concern is maximum traction to put power to the ground, and are not used in rallying.

<span class="mw-page-title-main">Tweel</span>

The Tweel is an airless tire design developed by the French tire company Michelin. Its significant advantage over pneumatic tires is that the Tweel does not use a bladder full of compressed air, and therefore cannot burst, leak pressure, or become flat. Instead, the Tweel's hub is connected to the rim via flexible polyurethane spokes which fulfil the shock-absorbing role provided by the compressed air in a traditional tire.

<span class="mw-page-title-main">Radial tire</span> Particular design of vehicular tire

A radial tire is a particular design of vehicular tire. In this design, the cord plies are arranged at 90 degrees to the direction of travel, or radially. Radial tire construction climbed to 100% market share in North America following Consumer Reports finding the superiority of the radial design in 1968, and were standard by 1976.

<span class="mw-page-title-main">André Michelin</span> French industrialist (1853–1931)

André Jules Michelin was a French industrialist who, with his brother Édouard (1859–1940), founded the Michelin Tyre Company in 1888 in the French city of Clermont-Ferrand.

<span class="mw-page-title-main">Rolling resistance</span> Force resisting the motion when a body rolls on a surface

Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation of the wheel, roadbed, etc., is recovered when the pressure is removed. Two forms of this are hysteresis losses, and permanent (plastic) deformation of the object or the surface. Note that the slippage between the wheel and the surface also results in energy dissipation. Although some researchers have included this term in rolling resistance, some suggest that this dissipation term should be treated separately from rolling resistance because it is due to the applied torque to the wheel and the resultant slip between the wheel and ground, which is called slip loss or slip resistance. In addition, only the so-called slip resistance involves friction, therefore the name "rolling friction" is to an extent a misnomer.

<span class="mw-page-title-main">Run-flat tire</span> Pneumatic vehicle tire

A run-flat tire is a pneumatic vehicle tire designed to resist the effects of deflation when punctured, allowing the vehicle to continue to be driven at reduced speeds for limited distances. First developed by tire manufacturer Michelin in the 1930s, run-flat tires were introduced to the public market in the 1980s. They have increased in popularity over time.

<span class="mw-page-title-main">Flat tire</span> Deflated pneumatic tire

A flat tire is a deflated pneumatic tyre, which can cause the rim of the wheel to ride on the tire tread or the ground potentially resulting in loss of control of the vehicle or irreparable damage to the tire. The most common cause of a flat tire is puncturing of the tire by a sharp object, such as a nail or pin, letting the air escape. Depending on the size of the puncture, the tire may deflate slowly or rapidly.

Tubeless tires are pneumatic tires that do not require a separate inner tube.

<span class="mw-page-title-main">Tire maintenance</span>

Inspection and maintenance of tires is about inspecting for wear and damage on tires so that adjustments or measures can be made to take better care of the tires so that they last longer, or to detect or predict if repairs or replacement of the tires becomes necessary. Tire maintenance for motor vehicles is based on several factors. The chief reason for tire replacement is friction from moving contact with road surfaces, causing the tread on the outer perimeter of tires to eventually wear away. When the tread depth becomes too shallow, like for example below 3.2 mm, the tire is worn out and should be replaced. The same rims can usually be used throughout the lifetime of the car. Other problems encountered in tire maintenance include:

<span class="mw-page-title-main">Bicycle tire</span> Tire that fits on the wheel of a bicycle

A bicycle tire is a tire that fits on the wheel of a bicycle or similar vehicle. These tires may also be used on tricycles, wheelchairs, and handcycles, frequently for racing. Bicycle tires provide an important source of suspension, generate the lateral forces necessary for balancing and turning, and generate the longitudinal forces necessary for propulsion and braking. Although the use of a pneumatic tire greatly reduces rolling resistance compared to the use of a rigid wheel or solid tire, the tires are still typically, the second largest source, after wind resistance, of power consumption on a level road. The modern detachable pneumatic bicycle tire contributed to the popularity and eventual dominance of the safety bicycle.

<span class="mw-page-title-main">Michelin PAX System</span>

The Michelin PAX is an automobile run-flat tire system that utilizes a special type of rim and tire to allow temporary use of a wheel if its tire is punctured. The core of Michelin's PAX system is the semi-rigid ring installed onto the rim using special equipment. It provides support to the tire and its sidewall to allow emergency operation at limited speed until such time as the tire can be replaced. Cars that use the system include supercars like the Bugatti Veyron EB 16.4, luxury cars like the Rolls-Royce Phantom, and more common vehicles like the Honda Odyssey and Nissan Quest.

<span class="mw-page-title-main">Outline of tires</span> Overview of and topical guide to tires

The following outline is provided as an overview of and topical guide to tires:

<span class="mw-page-title-main">Budd–Michelin rubber-tired rail cars</span> Rubber-tired rail cars

The Budd–Michelin rubber-tired rail cars were built by the Budd Company in the United States between 1931 and 1933 using French firm Michelin's "Micheline" rail car design. Michelin built its first rail car in 1929, and by 1932 had built a fleet of nine cars that all featured innovative and distinctive pneumatic tires. In September 1931, an agreement signed between the two companies allowed Budd to use the new rubber rail tires on its shot-welded, stainless-steel carbodies, and at the same time allowed Michelin to expand into the American market.

<span class="mw-page-title-main">Inner tube</span>

An inner tube is an inflatable ring that forms the interior of some pneumatic tires. The tube is inflated with a valve stem, and fits inside of the casing of the tire. The inflated inner tube provides structural support and suspension, while the outer tire provides grip and protects the more fragile tube. They are widely used in bicycles and are also used in many motorcycles and heavy road vehicles such as trucks and buses. They are now less common in other wheeled vehicles because of the benefits of having no tube, such as the ability to operate at low pressure and at high pressure, without going flat. Large inner rings also make effective flotation devices and are widely used in the leisure activity of tubing.

Steven M. Cron is a retired Michelin product research engineer and co-inventor of the Tweel.

References

  1. Bridges, Jake (November 9, 2022). "Airless Tires Pros and Cons". BestCarFinder. Retrieved November 10, 2022.
  2. "The airless tyre remains elusive". Outback Travel Australia. Retrieved 2021-11-28.
  3. "Rubber Spokes Give Bounce to Airless Safety Tires". Popular Science. May 1938. Retrieved 2015-10-20.
  4. Mihalascu, Daniel (2010-04-30). "Reinventing the Wheel: a Guide to Michelin's Airless Tire" . Retrieved 2015-12-31.
  5. Golson, Jordan (2019-06-06). "Michelin develops new airless tyre" . Retrieved 2020-08-03.
  6. Rutherford, Mark (2008-11-17). "New honeycomb tire is 'bulletproof'". CNET. Archived from the original on 2009-06-15. Retrieved 2008-11-23.
  7. Youtube video. Archived from the original on 2011-12-18. Retrieved 2011-12-27.
  8. Edelstein, Stephen (2013-11-18). "Polaris Airless Tires Go On Sale". Motor Authority. Retrieved 2015-02-15.
  9. Boyer, Mark (2011-12-31). "Bridgestone Air-Free Concept Tyre". inhabit.com. Retrieved 2012-04-19.
  10. Michler, Andrew (2011-12-28). "Airless, Springy 'Energy Return Wheel' Tire Promises To Improve Gas Mileage". inhabit.com. Retrieved 2012-04-19.
  11. Collie, Scott (2015-07-16). "Hankook's high-speed tests inch airless tires closer to production". GizMag. US. Retrieved 2016-10-02.
  12. Gessner, Daniel. "Why you can't buy airless tires for your car yet". Business Insider. Retrieved 2023-03-09.