Tyres to play a greater role in Green X Challenge
The American Le Mans Series, launched in 1999, is the first North American motorsport series to be acknowledged as a ‘green racing series’ by the United States Environmental Protection Agency (EPA), the United States Department of Energy and the Society of Automotive Engineers (SAE International). Since the 2009 season, American Le Mans has also been linked to the Michelin Green X Challenge, which elects a winner for each race based upon a combination of energy use, emissions, speed and efficiency criteria.
As the Green X Challenge heads to Monterey, California in May for the third round of the current American Le Mans season, Michelin reports that officials of the ‘Green Racing’ steering team are pondering the next step in the continued growth and development of American Le Mans. The steering team, which includes officials from the US Department of Energy, EPA and SAE International, plus the sanctioning International Motor Sports Association, is meeting with tyre makers in Monterey to discuss means to factor tyre use into the Green X Challenge formula.
“We all recognise how important tyres are to total energy use,” said Bob Larsen, senior technical manager of the US Department of Energy’s Green Racing Initiative and a charter member of the Green Racing steering team. “Now, we need to develop a plan to track tyre use and decide how to factor that into our formula for the Michelin Green X Challenge.”
In addition to reducing rolling resistance, tyres can also save energy through extended lifespan. It is through this second area that the Green Racing group sees significant opportunity for reducing overall energy use in a motorsports environment. “A single set of four passenger car tyres represents nearly 28 gallons of well-to-wheel oil use,” Larsen explained. “The figure is significantly higher for race tyres, and since every car uses multiple sets of tyres in each race, the cumulative energy impact is larger than most people realise.”
“From an energy efficiency and environmental perspective, reducing the number of tyres used during a race can provide significant benefits,” noted Scot Elkins, COO of the American Le Mans and series organiser the International Motor Sports Association. “Using fewer tyres eliminates the raw material and the energy used both in the tyre construction and in the manufacturing process. There are additional savings in the energy used in distribution and in recycling used tyres. It adds up to an enormous gain.”
Extending tyre wear and using tyres for multiple stints is already an important part of American Le Mans Series races and race strategies. Unlike other championships, which permit tyre changes to take place simultaneously with refuelling, the ALMS and the 24 Hours of Le Mans do not permit tyre changes while the car is refuelled. As a result, tyre changes typically add 12-14 seconds to a pit stop in the ALMS. The time spent at Le Mans, where only two crew members with a single air gun are allowed to perform tyre changes, is more than 20 seconds for each four-tyre change. The margin of victory at the 24 Hour race in 2011 was 13.8 seconds.
“Tyres are incredibly important in the ALMS and at Le Mans. We have open competition with four different tyre makers competing here,” said Elkins. “The tyre makers are continuously developing new technologies in order to multi-stint. The ability to double-stint – use the same set of tyres for two fuel loads – may well be a deciding factor in the race here this weekend.”
Michelin motorsports manager Silvia Mammone said the tyre maker supports the Green Racing group’s efforts to factor tyre usage into the Green X Challenge. “Tyres are an important part of energy usage and the technologies that enable us to reduce tyre usage in races is already being transferred to our street tyres,” Mammone commented. “Last year at Le Mans, the race winning Audi prototype used just nine sets of our tyres in the 24 hour race and was able to run five stints or over 454 miles on a single set of Michelin race tyres. That would have been impossible without continued development of new technologies.”