Green Tire Demand Boosts Fuel Ecoonmy Standards

Mon, 09/01/2014 - 13:59

With so many vehicles, it is no surprise that North America is the largest global market for tires. The US tire dealer industry includes about 11,000 companies with combined annual revenues of about US$30 billion. Most of the tires sold are replacement tires for passenger cars (50%) and commercial vehicles (20%), with the rest going to car manufacturers. The level of demand for tires is correlated with vehicle usage, which in turn depends on the economy. As governments continue to ratchet up fuel economy standards, car manufacturers have embraced the benefits of low rolling resistance tires. Rolling resistance describes the amount of energy dissipated when a tire rolls across the road. The greater the rolling resistance, the more energy the engine must generate to propel the vehicle and the more fuel the engine must consume to produce that energy. Thus, decreasing a tire’s rolling resistance is an effective way to increase a vehicle’s fuel efficiency.

A tire’s performance is determined by three main qualities: traction or grip, durability, and rolling resistance, besides attributes such as ride quality and noise. In the past, improving one of these qualities meant that the others suffered a decline. Thus, reducing rolling resistance had adverse effects on traction or durability. In recent years, however, thanks to improvements in tire materials and technology, it is possible to increase tire fuel efficiency without having an adverse effect on other performance attributes. Due to innovative high performance rubbers, tires have improved in all performance criteria. Today, it is possible to improve all factors simultaneously. The result is a growing market of fuel efficient tires that save consumers money by reducing fuel consumption and emissions, which protect the environment and lower dependence on foreign oil in countries such as the US. Tire technology continues to improve, holding the promise for even greater benefits in the years to come.

Tires are low hanging fruit from an automaker’s perspective as it is possible to improve fuel efficiency significantly without incurring high costs. It is much harder to improve fuel efficiency in the engine or the design of the car body. According to calculations, every percent of fuel economy gained by improvements to the engine costs a carmaker somewhere between US$30 and US$40 but a 1% improvement through an upgrade to the tires costs far less than that, at between US$6 to US$8. This makes improvements to tires one of the most cost effective technologies for automakers to meet rising fuel economy standards. Hybrid electric and pure electric vehicle fuel economy is more sensitive to tire rolling resistance because these cars tend to be heavier due to their large batteries and extra weight, which means more fuel consumption.

This is why most new hybrid cars now come outfitted with low rolling resistance tires. The typical consumer who replaces original equipment tires with a set of four low rolling resistance tires can save at least US$150 in fuel over the life of the tires, according to calculations made based on average US prices of gasoline. Considering that a low rolling resistance tire costs on average only US$20- 30 more than an aftermarket tire sold now, the benefits to consumers are clear. At higher oil prices, as has been the case in recent years, lifecycle savings with low rolling resistance tires are close to double.

The selection of materials has a very large impact on a tire’s rolling resistance. About 50% of the energy dissipation in a tire occurs in the tread, and the types of materials used there have a large effect on rolling resistance. The key challenge is to formulate polymers that have low visco-elastic losses but still maintain tire grip on the road. Specialty chemical manufacturers such as LANXESS have focused on the development of exactly such polymers suitable for tires. For example, LANXESS has unveiled polymers that have been produced with neodymium catalyst systems (Nd-BR) to be used for tire compounds showing the potential for simultaneously improving rolling resistance and durability. The Nd-BR compound also has very good resistance to flex cracking and fatigue. Additional advancements in materials technology through tailored structures is widely expected and could lead to new materials that have directionally tailored properties best suited to tire construction.

In Europe alone, according to the Clear Air Initiative, studies have shown that introducing green tires and labeling could result in a reduction of some 20 million metric tonnes of CO2 emissions and fuel savings worth US$8 billion annually. As such, from November 1, 2012, any tire sold within the EU has to have a sticker that shows its rolling resistance, wet grip, and noise performance. European policymakers want tomorrow’s cars to have much lower CO2 emissions through technological innovations like low-carbon-footprint biofuels, green tires, and lightweight plastics. It is not only the EU that is implementing tire labels. Countries such as Japan and South Korea have already implemented tire labels. Brazil is already preparing to introduce a tire label in 2016 and other countries like China will likely follow. In conclusion, tire labeling is an essential tool to making the market for low rolling resistance tires more efficient and transparent and to help consumers make more informed decisions. It is an easy way to achieve increased fuel economy while improving safety and reducing greenhouse gas emissions.