Noair: Toyo Tires launches latest non-pneumatic concept tyre
For the past 11 years, Toyo Tire & Rubber has engaged in research into the viability of airless tyres that deliver comparable performance to their pneumatic counterparts. The Japanese manufacturer first presented a prototype product at the Automotive Engineering Expo in May 2012 to demonstrate what it had achieved since 2006. Toyo Tires says it has since made “fundamental changes” to the structure of its airless tyres and has resolved various issues. The resulting improvements, it adds, are “substantial” and allow practical driving upon the latest generation of tyres. The company recently released its latest generation of airless concept tyre, the ‘noair’.
Beneath the tread rubber, the noair concept contains highly-rigid resin spokes to support the load demands placed upon the tyre. An outer diameter ring between the spokes and the tread, made from carbon fibre reinforced plastic, serves to reduce the load imposed on the spokes.
While previous prototypes supported load through an elliptical spoke configuration, the latest version has evolved into an x-shaped spoke configuration. Toyo Tires states that durability has been improved by achieving a “completely unique support configuration form.” Furthermore, the number of spokes has been doubled from the previous model, thereby better distributing contact pressure and reducing the impact noise generated when the spokes come in contact with the road surface, leading to a quieter ride.
According to Toyo Tires, evaluations conducted at one of its proving grounds in Japan show the noair tyre’s durability to not only be at least eight times better than that of previous prototypes, it also “vastly exceeds the equivalent legal and regulatory requirements” for the pneumatic tyres that Toyo Tires sells. Rolling resistance is at least half that of previous prototypes and 25 per cent better than Toyo Tires’ commercially-available products (Toyo compares the noair to its Toyo Teo+, size 155/65R13, mounted on a 13×4.5-J rim at an air pressure of 200/220 kPa. The noair has an external diameter of 540 mm, width of 140 mm and a rim equivalent to 14 inches). Wet braking distance has been improved by four per cent thanks to the use of a tread compound that utilises Toyo’s Nano Balance Technology. Road noise is significantly improved compared to previous prototypes, and is at a similar level to that of Toyo’s current pneumatic tyres.
When fitted to an actual car, Toyo Tires says that while there are “still some issues related to noise within the vehicle and ride quality,” significant improvements in handling stability and external noise have narrowed the gap between Toyo’s airless concept and its commercial products in most indices. The company says it will continue research into the concept, adding that it is considering shifting its focus from the laboratory to marketing considerations.