Firestone chief race tire engineer Cara Adams explains the changes made to the brand's Verizon IndyCar Series tires after new low-downforce bodywork was introduced for 2018.

RACER's Marshall Pruett and Dale Coyne Racing's Sebastien Bourdais break down the first day of practice at St. Petersburg where teams and drivers got to grips with new low-downforce bodywork and revised tires from Firestone.