vic_s197

It doesn't vibrate at idle just anything above 20 mph I can feel it pretty good and my passenger seat vibrates while driving. Iv researched and found a lot of trucks are doin this anybody know why? I just put new tires on it bfg all terrains 275/65's but it vibrated before the new tires. Also they are at 65 psi and the ride is a little rough , should I drop the air pressure to around 55 psi?