Tire maker has a crush on oranges

PHOTO SUPPLIED

Yokohama applies nanotechnology to get orange oil to bond with natural rubber to provide seemingly opposite properties in its new dB Super E-Spec.

John Mahler

SPECIAL TO THE STAR

In the tire industry, "orange" is the new green.

That's particularly true at Yokohama Tire, which has been using orange rinds to reinforce the properties of natural and synthetic rubber.

The result is a tire with low rolling resistance, preferred for hybrid cars, yet has good stick for acceleration and braking. These are not necessarily complementary characteristics – until now.

I have touched, driven and licked the new dB Super E-Spec tire by Yokohama. It has the lowest rolling resistance of anything Yoko has made to date. It drives like a normal tire and remarkably, it does not taste of orange or have a fruity smell.

While this tire is aimed at the current hybrid cars on the market, it can be used on other vehicles as well to save fuel. It goes on sale in October well into the orange-picking season down south.

To fully understand why every tire in the marketplace is not a fuel economy tire, let's look at the engineering contradictions involved its design.

To get good fuel economy a tire must have low rolling resistance. Rolling resistance has many components but the main one is friction where the tire touches the road. When we drive straight ahead, energy is lost by the road surface/tire interface because both are rough and they grab at one another.

An example of good rolling resistance would be a streetcar. It has smooth steel wheels and the rail is smooth steel, so not much trouble rolling along.

When it comes to corners, lack of rolling resistance is a very bad thing, that small friction patch between the wheel and the rail does not have the necessary grip to go around a corner. That's why streetcar wheels have lips to keep them on track. Lips on car tires are a non starter.

Exactly the same contradiction occurs in cars: We'd like low rolling resistance when going straight, but lots of friction when we try to go around a corner. The magic bullet is orange oil. Not just orange oil but orange oil in a mixture of natural rubber, charcoal-derived carbon, silica and some oil.

This is not something for a KitchenAid mixer. Yokohama engineers knew that the molecular chains of natural rubber and orange oil are similar and so would combine well; however adding the rest of the slurry and making sure it all stayed bonded required resorting to nano technology.

As engineer Greg Cressman explained, nanotechnology – components engineered at one nanometre or less, which is one billionth of a metre – is the key to developing the chemical bonds that go into making a tire.

"The tight chemical bonding of the elements results in a dense tread compound that enhances contact area five to 10 per cent without increasing tread size."

"Tires made with natural rubber have inherently lower rolling resistance than do tires made with synthetic rubber.

But natural rubber does not generate the heat (via friction with the road) needed to provide superior traction.

Yokohama's nano-engineering bridged the gap between the low rolling resistance properties of natural rubber and the superior grip of synthetic rubber."

"Injecting orange oil into the gaps between firmly intertwined polymers softens the natural rubber. The result is a compound with the lower rolling resistance of natural rubber but one that is able to quickly generate the heat (and traction) for braking and handling. The addition of the orange oil helps the rubber to adhere to even minute features of the road surface while reducing rolling resistance by 20 per cent."

In other words, this tire is very stiff when going straight but quickly softens with the heat created friction of going around a corner. The super quick softening of the compound gives superior lateral grip relative to a normal tire.

This entire tire is manufactured with 80 per cent non-petroleum products. That is amazing. Orange oil replaces most oil, Rayon made from wood fibre replaces synthetic polyester in the belts, and charcoal derived carbon replaces petroleum derived carbon.

The Japanese plant that makes this tire boasts zero emissions. By that they mean everything that enters the plant comes out as a tire, and no scrap waste is produced.

Another feature of the tire responds to people's inability to check the air in their tires. An underinflated tire is a fuel-thirsty tire. Yokohama decided to be proactive and designed a new inner liner for this tire.

Instead of just rubber, it is again a new polymer of very light strong plastic film. The normal loss of one pound of pressure per square inch a month is stopped and the tire weighs about one pound less than using a normal butyl rubber liner.

Since the tire was intended for hybrids, it had to be quiet. So the E-Spec became part of Yokohama's dB tire line.

This family has been in production for some years, its focus has been on silent running. This new addition is no exception.

It uses staggered tread blocks from one side to the other of the tire to cancel pattern noise from the road and separated the larger ribs around the tire into 144 small blocks.

And to help diminish reflected road noise the tire's sidewall has vibration cancelling grooves.

In launching this tire Yokohama Canada marketing executive Jonathon Karelse says, "There are currently more than 25,000 hybrid vehicles on the road in Canada and that number is expanding daily. Providing a replacement tire that meets these owners' high expectations for environmental performance – from design to manufacture to use – puts Yokohama on the ground floor of a market that we think will only grow in size and importance," Karelse says.

In tests against tires in its class, the Yoko has 11 per cent to 22 per cent less rolling resistance.

Four popular sizes of the new dB super E-spec tires will be available from Yokohama dealers and participating auto dealerships: P185/65R15, P195/65R15, P195/55R16 and P215/60R16.

Email tire questions to John Mahler at thetireguy_1 @ hotmail.com. Please include vehicle's make, model and year, tire brand and size, as well as your name, address and phone number. Volume of mail prevents us from answering all queries or providing personal replies.

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