Current rubber tyres:
Rubber tyres heavily damage our environment. With a lifespan of 3-7 years (or a distance of 20 000 miles), only 13% of used rubber tyres are recycled. Most tyres, between 1 – 1.8 billion of used rubber tyres per year, are disposed (burnt or dumped) worldwide, equating to 2-3% of all waste material collected, while two thirds of used tyres are dumped in landfills. Many scrap yard owners incinerate the tyres to free up space, contributing to carbon dioxide emissions. In landfills, heaps of waste tires can burn constantly for up to months, producing carbon dioxide, and carcinogenic and mutagenic toxins harmful to humans.
Further on, toxic heavy metals leach from disposed tyres at landfills, and into the soil, contaminating soil and water reserves. Contaminated water and soil affect ecosystems, killing plants and animals, and eventually work up the food chains to humans. Tyres exposed to sunlight also release toxic chemicals into the air.
Growing rubber for tyres also proves to be an environmental and ethical issue.
Why is it so difficult to reuse or recycle used rubber tyres?
After its lifetime, the quality of the rubber degrades. New tyres made from old recycled tyres often turn out to suffer from reduced tread life and traction, therefore not making it worthwhile for most tyre manufacturers. Moreover, most people avoid the hassle of recycling tyres, as they are bulky and difficult to transport to the few recycling points available.
Introducing Nitinol tyres:
Nitinol is a smart material, a shape memory metal alloy composed of 55% nickel and 45% titanium. This shape memory
alloy can go back to its original formed shape (in this case of a tyre) if deformed, by applying heat and cooling. Superelastic above certain temperatures, it can withstand excessive deformation, and is long-lasting and bullet proof.
Nitinol tyres thus have a much longer lifespan (), and lower maintenance cost than rubber tyres. They are lightweight and reusable, as at the end of its lifetime, it can just be heated so it returns to its original shape and treated with an oxidation protection coating. It is safe, as it eliminates possibility of puncture failures. A few of its advantages are here listed:
- Safe: eliminates possibility of puncture failures
- Strong: can widthstand excessive deformation
- Robust: offers traction equal or superior to usual rubber tyres
- Simple: no need to pump in air
- Lightweight: no inner frame needed for wheel assembly
- Versatile: tyre stiffness can be designed to limit energy transferred to vehicle
Apart from mining the metals, Nitinols contribute truly little to pollution, making it potentially an interesting alternative to rubber tyres, allowing us to reduce rubber consumption significantly. Nitinol tires were developed by NASA for their rovers, but are also being developed now for terrestrial use, most notably for cars.