Despite having won every American Le Mans Series street race at the time, Michelin rolled out with a revolutionary new tire construction for the St. Petersburg and Long Beach rounds in 2008 that helped put the French tire manufacturer in the record books.
The ‘Street Soft’ construction, born from an Audi tire test in Europe with its venerable R10 TDIs, was offered to all of Michelin’s LMP1 and LMP2 technical partner teams and provided increased grip on the often abrasive and slippery concrete canyons.
“Grip is always at a premium on temporary circuits, so we wanted to provide our teams with a ‘softer than soft’ option tire, but one that still delivers extended durability and consistency,” said Michelin’s then-ALMS technical team leader Karl Koenigstein.
After struggling at both circuits the year before the diesel-powered Audis shined on the Street Softs in St. Pete, with Marco Werner setting a new track qualifying record en route to pole position.
Lucas Luhr’s bold, three-wide outside pass into Turn 1 on the final restart around Penske Racing’s Romain Dumas with three minutes to go netted the German his first overall ALMS victory, and first for Audi on a street circuit in more than a year.
“We were surprised at how well the car was going here. We knew we had a good car with good grip,” Luhr said post-race.
The impressive performance came after Audi’s Friday pace-setting time was bettered by only one IndyCar on the day.
Two weeks later, Audi claimed a 1-2 finish on the streets of Long Beach, with Werner and Luhr again victorious, but this time giving Michelin its milestone 250th ALMS class win.
As was the case at St. Pete, the Audis, Penske and Dyson Racing’s Porsche RS Spyders, plus the Acura ARX-01bs from Fernandez Racing, Andretti Green Racing and Highcroft Racing, all took advantage of the Street Softs.
“The new Michelin ‘street soft’ tires gave us a good grip level and we saw from the beginning that the car would be good in the race,” Werner said.
Werner and Luhr went on to claim a further four overall wins that year, while up against the might of the Porsches and Acuras, as well as the LMP1 championship.
Street Softs 2.0
Michelin’s Street Softs, meanwhile, were no longer used following Audi’s withdrawal from full-season ALMS competition at the end of the year.
However, a new-generation ultra-soft tire, dubbed ‘Street Soft 2.0’ was developed for Muscle Milk Pickett Racing’s HPD ARX-03a LMP1 car in 2012, which saw Luhr and Klaus Graf double-stint to victory not only at Long Beach, but also at Mazda Raceway Laguna Seca.
“By then we had been able to migrate our tires over half a range softer,” said Ken Payne, Michelin North America technical director of motorsports.
“We still called them ‘street softs’ because of the construction, but we were using what we now considered a medium tread compound.
“People were shaking their heads at how we could possibly double stint super ‘soft’ tires on a permanent circuit.”