Michigan set up to be final race test for 2017 aero package

— -- NASCAR mulled three choices on which rules package it would use at Michigan International Speedway this weekend.

It could have gone with the current 2016 aerodynamic package, which would give valuable data on how the 2016 package performed vs. the proposed 2017 rules, which were run at Michigan in June. But with NASCAR already believing it would make the changes for 2017, there was little reason for this additional data.

NASCAR, though, is thinking about tweaking its proposed 2017 rules to help address the two main complaints -- too much front downforce when balanced with the rear downforce, and too little sideforce that made the cars turbulent when side-by-side.

But then NASCAR decided the other option -- run the exact same specifications as in June one more time -- would work best so teams could build on what they learned in the races at Michigan in June and Kentucky in July. The specifications reduce the amount of downforce and sideforce that has been the trend for NASCAR the past couple of years.

NASCAR reduced downforce by about 900 pounds for this year, with a target of 1,800. The teams have gotten back a few hundred, and NASCAR hopes the new package will have 1,600 pounds of downforce. That's down from 3,500 a couple years ago. Side forces could be reduced by 125 pounds.

"Some of the teams said that they might want to do a little tweak [to the rules] but at the same time they said this depends on mechanical grip so much, we still have some things we haven't tried," NASCAR senior vice president Gene Stefanyshyn said. "So we believe going to Michigan will give us that last piece of information."

NASCAR would like to get the 2017 rules package to the teams sometime in the next four weeks. Not only does that give the teams time to start building cars, but it also gives NASCAR a chance to work with Goodyear on deciding what tires will work the best at each track.

Goodyear will bring the same tire it brought to Michigan for the June race. NASCAR already has tentatively set a test for Martinsville once the rules package is confirmed.

"You get into the corner with the car that already doesn't drive good and now you're putting it in a vulnerable position," said Joey Logano, who won the Michigan race in June. "It's a good thing. Don't get me wrong. That's what we need.

"We need crazy interesting stuff. ... We have more crashes because they're really hard to drive and it's hard to make the moves, and guys are getting loose underneath each other or tight and sliding up."

The package reduces the spoiler from 3.5 inches high and 61 inches long to 2.5 inches high and 53 inches long, and adds a deck lid fin. It also has decreased the surface area of the front splitter that sits underneath the car by about three inches. NASCAR also will eliminate any rear skew -- the angle of the rear housing that helps cars turn and create side force.

At a track such as Michigan, the drivers enter the corner with these changes a little bit faster but have to reduce speed by more than 10 mph to drive through the turns. Drivers have wanted less corner speed, which not only allows more passing but also could decrease the harshness of a crash in the corner.

Both the 2-mile Michigan and recently repaved and reconfigured 1.5-mile Kentucky have been challenging tracks for NASCAR to have good races, at times having one primary fast groove and with cars getting strung out.

"I'd love to see [this package] on a short track," said six-time Sprint Cup champion Jimmie Johnson. "I'd love to see it on [another] 1.5-mile before we make a decision and move on. But the truth of the matter is we don't have that luxury, especially when we get into the Chase."

The teams have told NASCAR that they do not want to test the 2017 package during the Chase, that they have spent the season developing the current package and can't afford that new twist.

NASCAR agrees, and just like a year ago, it won't make changes for the final 10 races of the season.

"It's cool that you can run closer to the back bumper of somebody, but there must be a lot less sideforce because now when you're next to somebody, it's a handful," said Kyle Larson, who likely needs a win in the next three races to make the Chase. "I wish we could take this package somewhere that's got a better surface.

"Michigan is already pretty narrow, Kentucky with the brand new repave definitely was one lane. ... I know Chicago is in the Chase, but Chicago would be the perfect place. It would be cool to see what it's like where you're not really running on somebody's door because the lanes are so narrow because I think the racing would be that much better."

One thing drivers do expect: chaos on restarts.

"I expect there be lots of wrecks on restarts," Larson said. "It's always sketchy there no matter what package we take to Michigan on restarts. Especially that last race there, it was a handful."