Rubber,

I had my vibration when car was first received @ 80mph. Dealer sent me to goodyear down the street. I was very pleased, a manager drove car on lift slowly & carefully. Then removed lug nuts by hand no impact and removed all wheels. each wheel to high speed balance machine, knocked off factory weights, spun and re-applied weights at desired points. They placed weights in rows of two instead of an 7-8 inch single strip from factory. This way the weight was placed closer to where the machine was calling for it to be. It corrected my issue. Then three people checked and signed off lug nuts hand torqued to 150#. I was very pleased!