NASCAR cuts testing, changes tech package, adds rain tyres for 2015

Under the new rules, which were unveiled on Tuesday, teams will no longer be permitted to test independently, and will instead be restricted to NASCAR or Goodyear tests.

Other changes include a reduction in horsepower (which is expected to slow the cars by around 6mph and encourage passing), a shorter rear spoiler, lower differential gear ratios, and an optional driver-adjustable track bar.

Additionally, group qualifying will be introduced at the Daytona 500 for the first time.

"This race package represents a lot of hard work by NASCAR, the race teams, the drivers, our manufacturer partners and Goodyear," said Gene Stefanyshyn, NASCAR's senior vice president of innovation and racing development.

"We've remained committed to constantly looking at our racing, and the work that has been done has been aimed at getting a rules package delivered to the race teams as early as possible."

The changes also provide for the expected reintroduction of rain tyres in the event of a wet race on a road course.

"We're very pleased with the rules package and what it will do for our racing," said Steve O'Donnell, NASCAR executive vice president and chief racing development officer.

"We're confident it will continue to generate great racing, along with continuous safety improvements."