The h7 rtr has a c-hub suspension setup.The pbs stands for pivot(pillow)ball suspension.I like the pbs setup because its much quicker to change the camber/toe settings at the track.Just reach an allen wrench through the spoke wheels and screw or unscrew the pivot balls to change your settings.The only thing i didnt like was the ball shafts kept bending and it would kill my steering.But not any more