Tweel Airless Tires

Can you imagine a driving experience where getting a flat tire was never a concern? It may sound too good to be true, but the engineers at Michelin have been working on that very dream since 2005. Tweel Airless Tires are a combination tire-wheel (hence the name) that relies on a whole new construction, eliminating air pressure altogether. So, how does it work exactly? And why the heck can’t we buy it right now!?

Michelin Tweel Airless Tire In Action
Photo credit : http://www.michelintweel.com/aboutTweel.html

The construction of the Tweel airless tire is relatively simple. At the center is a deformable hub that connects to the vehicle itself. The hub is surrounded by a series of flexible polyurethane spokes, which support an outer shear band, covered by conventional rubber tire tread. The tread itself can be designed just like it is today in pneumatic tires, and is replaceable when worn. The flexible spokes absorb shock in the same way that air absorbs shock within a typical tire, and the hub is able to flex under various loads and spring back to its original shape. The spokes can be made with a wide range of stiffness, offering many different handling and load capabilities.

Michelin Tweel Airless Tire Cutaway
Photo credit:
http://www.michelintweel.com/whyTweel.html

The benefits of this construction are numerous! There is the obvious elimination of tire punctures and/or blowouts; this makes tires safer, less expensive, and much longer lasting. Michelin has also claimed the tread itself will last 2-3 times longer than normal tire rubber, and falls within 5% of rolling resistance of its pneumatic tires (this means it’s within a 1% range of fuel efficiency of regular tires). In terms of handling, Tweel Airless Tires offer a unique advantage – in normal tires, a more cushiony ride leads to a decrease in handling (and vice versa), since both ride quality and handling are related to the air pressure and sidewall stiffness within the tire. With a Tweel Airless Tire, these aspects can be controlled independently of one another. This means the flexible spokes offer a cushiony, flexible ride, while the lateral stiffness (and overall handling abilities) can be tuned separately. The combination of producing less waste and eliminating the driver’s need to help fuel efficiency through air pressure monitoring make the Tweel airless tire much more environmentally friendly, too.

There are some downsides, unfortunately. The most notable issue preventing its mass marketing is heavy vibration above 50 mph. This leads to unpleasant noise levels and excessive heat production. While these are issues that will surely be fixed over time by Michelin engineers, there exists another problem largely out of their control – the tire and auto industries as a whole. There are literally thousands of tire factories, auto shops, dealers, auto makers, etc. that would have to change their business models entirely to accommodate such a radical shift. In terms of marketing, equipment, technical training, and development, it almost seems impossible. Of course it is not impossible, but experts agree that it will be quite some time before the Tweel airless tire is available to passenger vehicles and consumers in the common marketplace.

There are some current applications for this cool technology, though. Various construction and military vehicles are already taking advantage of the Tweel airless tire. Since they’re not high-speed vehicles, they don’t run into the excessive noise and heat problems that standard passenger vehicles do. Tweel airless tires have also been showcased on the Segway Centaur (an ATV 4-wheeler) and the iBot (a mobility vehicle for the physically impaired).

Tweel Airless Tire In A Commercial Application
photo credit:
http://www.michelintweel.com/aboutTweel.html

This is an exciting technology to watch develop, and will surely revolutionize the tire industry as a whole. While we’re just as excited as the next person to see these tire alternatives hit the stores, just remember – patience is a virtue, and good things come to those who wait.

In the meantime, check out AutoSquad for all your regular tire needs! Contact us at 855-484-3778, or visit www.AutoSquad.com to see our tire selection and make an appointment online. Please note that AutoSquad’s service is currently available in the Washington, DC metro area only.

Michelin’s PAX tires are zero-pressure tires that take an alternative approach to the whole concept of driving on tires that have lost all their air pressure. Traditional run-flat tires rely on heavily reinforced sidewalls and a specially-designed bead, whereas PAX tires use a semi-rigid insert mounted inside the tire and an asymmetric wheel and tire design to provide the support needed to drive an extended distance on what would otherwise be a flat tire. PAX tires offer several advantages and disadvantages over traditional run-flat technology. Even though they have been used sparingly, PAX tires deserve some consideration by consumers interested in the concept of run-flat technology.

Run-flat tires were introduced in the mid-1990s when both - Goodyear Tires and Michelin Tires – offered zero-pressure tires. These tires were designed to run for a limited distance at a limited speed with no air. The concept was essentially the same as a standard tire, except that the sidewalls were stiffened to support the entire weight of the vehicle, and the bead was redesigned to provide extra support for the sidewall while maintaining contact with the wheel. The downside was that the heavier sidewalls made for a stiffer ride.

Michelin introduced PAX tires in 2000 to circumvent the ride issue related to run-flat tires. Instead of the heavier sidewalls, PAX tires offered a more conventional sidewall. They relied on a polymer insert mounted inside the tire and against the wheel (essentially a plastic tire mounted inside the rubber tire) to support the weight of the vehicle in zero pressure conditions. The entire wheel and tire assembly had to be redesigned to accommodate this new concept. According to Michelin, PAX tires return a more conventional ride to the vehicle by providing better handling through reduced tire roll and better fuel economy. Perhaps this is why they were used for vehicles like the Bugatti Veyron and Honda Odyssey.

Unlike other types of run-flat tires, PAX tires can be repaired just like a conventional tire by patching from the inside. They are designed to travel up to 125 miles with no air, at vehicle speeds of 55 miles per hour. This betters the alternative run-flat tire design of 50 miles at speeds up to 50 miles per hour. A special gel coats the polymer insert to keep it lubricated when running against the inside of a flat tire.

The PAX tire system was installed as an original equipment option on only 3 models in the US for a limited time – Honda Odyssey Touring (2005-2009), Nissan Quest SE 3.5 & SL 3.5 (2006-2007) and Acura RL (2006-2008). This system does have some disadvantages which prevented its larger adoption. PAX tire system weighs approximately 4.7 times more than a standard wheel-tire assembly and their overall design introduces a high rotating mass and unsprung weight, which puts additional strain on suspension systems and brakes. Although they can be repaired conventionally, the unique design and construction requires that they be repaired using special equipment. Most tire shops have decided against investing in this equipment because the cost of the equipment outweighs the potential revenue opportunity. Therefore, owners of the aforementioned models are expected to bring their vehicles to a specially-equipped service facility which may not be readily available everywhere in the country. And although Michelin is licensing the technology, no other manufacturers have yet capitalized on that opportunity, meaning owners are still locked into Michelin as the supplier of replacement tires. PAX tire system is not expected to be installed as an OEM option on any new vehicles produced in 2012/2013. It is our recommendation that you consider the pros and cons of this technology prior to investing in a pre-owned vehicle with PAX tires.

For more information about PAX tires, visit our website and connect with us on Facebook and Twitter.

Comments?

Do you have a vehicle with PAX tires? If so, what do you think of them? Have they made your drive safer? And, more importantly, where did you take them to have your last set replaced?

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Category Archives: Michelin

Tweel Airless Tires

Tweel Airless Tires

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