NASCAR has passed a rule that will curb the ability of teams to set their cars up in a way that gives the driver easier rear steer.
A technical bulletin was issued by NASCAR on Thursday and goes into effect next week at Chicago, when the Chase for the Sprint Cup championship begins.
Drivers have alleged Hendrick Motorsports has made gains in the rear housing this season that has given its cars an aerodynamic advantage. NASCAR has maintained through the complaints that the Hendrick teams weren't breaking any rules.
Starting next week, a size of a piece of rubber called bushings that is located near the rear mounting points will have to meet a new maximum size.
The bushings were being manipulated to have more give and allow drivers more control of their steering as they went through the turns.
