NASCAR cuts downforce for 2016 Sprint Cup to improve racing

The series tried various different rules tweaks during the summer as part of an ongoing investigation into how to spice up its on-track product following a spate of disappointing races.

Next season it will mandate a 3.5-inch spoiler, a 0.25-inch front leading splitter edge and a 33-inch wide radiator pan as its "base package", having trialled a similar configuration in this year's Kentucky and Darlington rounds.

NASCAR's executive vice president and chief racing development officer Steve O'Donnell said: "NASCAR has worked tirelessly with our teams, drivers, manufacturers and Goodyear to develop a rules package that provides fans with the best racing possible.

"The success of the races at Kentucky and Darlington in similar trim proved extremely valuable in accelerating rules development for 2016.

"Now, as teams have even more time to prepare and a strong baseline of data, we anticipate the racing to be even better."

Variation in gear ratios and Goodyear's tyre compounds will be used to adjust the package to the different types of circuit on the calendar.

NASCAR had also experimented with a high-drag configuration for its higher-speed tracks, but O'Donnell believes the low-downforce set-up will suffice everywhere and prevent teams having to spend more on perfecting varied packages.

"There are also costs involved that we've got to manage with the teams," he said.

"Ultimately what do we think is going to put on the best race? What we kept coming back to was looking at the low downforce package.

"What steered us away initially was the speeds that we would potentially be running at Michigan.

"But in sitting down with Goodyear and the industry, I think we've really hit on the ability to match that tyre with the configuration we have now and feel really good about the direction we're going for all those tracks outside of superspeedways to deploy the low downforce package."

After experimenting with the various configurations during the summer, NASCAR opted to wait until 2016 to make wholesale changes rather than implementing the new options for this year's Chase - a decision O'Donnell defended.

"There were certainly discussions about the timing and when to deploy a low downforce package, but a number of tests had already been conducted for the final 10 races, a lot of investments had been made, and as we went around and talked to the industry, the decision was made: let's stick with what we have for 2015," he said.

"Not all drivers agreed, certainly, but the owners and a lot of the industry [did].

"That's the known. That's what we've put all our resources towards."