I'm getting a shaking in the rear of my 2007 Nissan Quest just put newer tires

What is your question?

Getting a shaking in the rear end of my 2007 Nissan Quest just put on new tires but it is still happening it's only at a higher speed what could it be

What makes this problem better or worse?

Usually speeds over 50

How long has your 2005 Nissan Quest had this problem?

A few weeks