My Audi A6 vibrates when i drive. when i applyies the brakes and car get slow it vibrates more and it is very annoying. I have checked the tires for low air but nothing wrong. This bubbling of the car is increasing day by day and the only thing that I know is the rear tires are about to worn and I have been suggested the tires change and also the brake pad changes. I just wanted to know is this only becuase of this or could be something else?

 

In addition to the aforementioned brake pads (and rotors) and tires, I would also check for torn CV Joint boots. Just rub your hand on the inside of each wheel; if you come out witha bunch of grease you have a winner - well... not really, but you may have found the source of your vibration. As the boot tore and lost the grease in it the joint starts to wear out and rubs metal to metal without any lubrication.

 

tie rods or control arms tend to wear by now also (guessing you have an 02-04 A6 2.7t)

 

brake rotors being warrped is causing your pulsation when breaking. If your tires are worn, replace them, they are probably out of balance causing a vibration also.