the BEST way to beat chase missions is to be in a helicopter, land to block their path, and then cut the dude to pieces with the helicopter blades when he gets out of the car
i hate chase missions on bikes. the worst was the fucking moped one. i kept crashing or doing dumb shit. then finally on the last try of the night i got on and the dude who owned it threw me off.
That moped one was gay. Very very homosexual. I lol'd.
But I finally beat it by firing an RPG at him. Then I went ahead and shot the owner of the other 2 moped because they consistently threw me off when I first started the chase. Pay back is a bitch.