Tire Efficiency Consumer Information BETA

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Its A Small World After All

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It’s A Small World After All
Moderator, Nov. 21, 9:45 AM

You might be wondering what prompted all this concern about whether consumers understand how tires affect fuel efficiency. As part of a bigger study on reducing US dependence on foreign oil, Congress found out that if consumers chose more fuel efficient models when they replace their tires, the fuel economy of existing passenger vehicles could be improved by 1-2%. This may not sound like much, but it translates to the US saving 1-2 billion gallons of fuel per year.

NHTSA is not the only government agency working on this. The California Energy Commission has been developing guidelines for fuel efficient tires. The European Union is about to adopt a fuel efficiency consumer program that will require labelling tires with fuel efficiency information.  Japan is also studying the area. Worldwide, the potential fuel savings start to add up.

Because large tire manufacturers like Michelin sell in a global market, NHTSA has to walk a fine line when it comes to coordinating its requirements with those of these other governments, particularly the EU.  It’s expensive for manufacturers to have to produce different testing data, labels and other consumer materials depending on whether a tire is going to be sold in Germany, New York, or California.  Those costs may end up as higher tire prices for consumers.  So, NHTSA has tentatively decided to use the same testing procedure (created by the International Standards Organization) that the EU will require.

But at the same time, NHTSA’s responsibility is to come up with the consumer information program that’s best for US tire buyers.  So, it’s proposing to use a different way to measure the “rolling resistance” that determines a tire’s fuel efficiency than the EU is using.  The EU plans to base its rating on the “rolling resistance coefficient” (rolling resistance divided by the “load” the tire was tested at).  NHTSA is proposing to use just the rolling resistance number.  It compared possible tire choices for three different-sized vehicles (a Chevrolet Impala, a Chevrolet Silverado, and a Toyota Corolla) and found that a 10 point improvement in a 0 to 100 rating system based on the rolling resistance measurement corresponded to a similar amount of fuel saved in all three situations. If, however, the rating system were based on the rolling resistance coefficient, a 10 point improvement would translate to a smaller amount of fuel saved for a small car and larger fuel savings for a large car. NHTSA thinks that consumers will have a harder time using a rating system in which point differences on the scale represent different gains in fuel efficiency depending on the size of their vehicle.

So, what do you think? Is NHTSA right in its prediction about which kind of rating system will be easier for consumers to understand and apply — and in its judgment that this outweighs the costs of making tire manufacturers comply with two different sets of regulatory requirements?

HAVE YOUR SAY by replying below, or DIG IN to learn more about the testing procedure and the rolling resistance formula.