Officials of the Green Racing steering team that oversees the MICHELIN® GREEN X® Challenge are pondering the next step in the continued growth and development of America’s premier environmental motorsports competition.

The Green Racing steering team met with tire makers here on Thursday to discuss means to factor tire use into the formula that currently includes energy use, emissions, speed and efficiency. The officials include representatives of the U.S. Department of Energy, EPA, SAE International and the sanctioning International Motor Sports Association.

Tires affect energy use in two ways, according to Bob Larsen, senior technical manager of the U.S. Department of Energy’s Green Racing Initiative and a charter member of the Green Racing steering team.

“Passenger car tires can save energy by reducing the rolling resistance—which accounts for nearly 20 percent of the energy used to push a vehicle along the road—and by reducing tire use through extended tire life,” said Larsen.

In motorsports, it is in the second area, reducing tire use, that the Green Racing group sees significant opportunity for reducing overall energy use in a motorsports environment.

“A single set of four passenger car tires represents nearly 28 gallons of well-to-wheel (WTW) oil use,” said Larsen. The figure is significantly higher for race tires and since every car uses multiple sets of tires in each race, the cumulative energy impact is larger than most people realize.

“From an energy efficiency and environmental perspective, reducing the number of tires used during a race can provide significant benefits,” notes Scot Elkins, COO of IMSA and ALMS. “Using fewer tires eliminates the raw material and the energy used both in the tire construction and in the manufacturing process. There are additional savings in the energy used in distribution and in recycling used tires. It adds up to an enormous gain.”

“Tires are incredibly important in the ALMS and at Le Mans. We have open competition with four different tire makers competing here,” said Elkins. “The tire makers are continuously developing new technologies in order to multi-stint. The ability to double-stint—use the same set of tires for two fuel loads–may well be the deciding factor in the race here this weekend.”

“We all recognize how important tires are to total energy use,” said Larsen. “Now, we need to develop a plan to track tire use and decide how to factor that into our formula for the MICHELIN GREEN X Challenge.”