NASCAR tries tweaks to help passing

NASCAR evaluated six different rule change options in a test at Michigan Speedway on Monday as it investigates ways to improve the quality of Sprint Cup racing for 2015.

Ten drivers from nine different teams took part in the test, which included two short mock races.

NASCAR's vice president of innovation and racing development Gene Stefanyshyn said the series was keen to answer criticism of the racing with the current package.

"We're looking for a fan-centric direction," said Stefanyshyn. "Fans have said they like a lot of passing, they like a lot of side by side, they like a lot of lead changes. So that's what we're endeavoring to do."

Changes tried during the Michigan test included aerodynamic adjustments, a cut in downforce levels, horsepower reductions and a change in Goodyear tire compounds. Stefanyshyn said whatever option was chosen was likely to make the cars slower.

"I think taking some speed off is the direction we're heading," he said. "As for the amount, we'll wait and see what information we get."