The purple Hellbear is a beast of a car; though very heavy compared to other cars because of its design and materials, it came with an extremely powerful engine that balanced out the weight-to-power ratio to compete with the other cars in the race.
As Adam stuck to the Hellbear's tail, he started gaining distance, but Adam didn't act recklessly. The car before him weighs at least one and a half times more than his; if, for some reason, the driver decides to play rough, no matter how skilled and inhuman Adam's ability is, he cannot beat physics.
So he keeps close and continues to swerve left and right to open up a path so he can take over, but the Hellbear's driver is not letting him.
The driver before him is clearly aggressive, and the car he is driving can clearly take a beating if things get rough; Adam doesn't have that luxury.
