At Michigan, drivers slip into next evolution of rules changes for better racing

Last year, NASCAR went to Michigan to test an aerodynamics package. Drivers hated it.

This year, NASCAR will unveil another aerodynamics package at Michigan, one of two tracks it will use as test beds for changes in 2017. Here's betting drivers will love it.

And there's a new buzz phrase in the conversation: side force. Downforce is what causes a car to stick to the track and prevent skidding in high-speed turns. The physics involved reduction of air pressure under cars to push them toward the racing surface.

Side force is tire slippage; at high speed, tires skid toward the outside of a curve when there is less downforce to keep them on their intended line.

What you need to know is simple: Less…