Board Thread:Game Discussion/@comment-30447859-20181205210614/@comment-37145414-20181205225440

Typically in road tests in the US, the grip is measured at 100 mph. Cars with active aero will have very different curves regarding how many gs at higher speeds. On Reddit the developers have also said that the calculation of PR doesn't account for active aero, so that makes two measures of performance that do not capture the full value (even within this game) of downforce at high speeds.