So I have noticed that my set of 18s that I bought used vibrates in the rear a bit when I hit 77mph and up. However, it doesn't do it all the time and the vibrating more noticible on certain pavements on the freeway. Does this sound like a wheel balancing issue? Thanks in advance.

 

Usually a balancing issue will appear most noticeably at around 60 to 65mph and up. Get them balanced, but also look to see if your wheels are hubcentric. If the center bore of the wheel is not snug with the hub, you need some hub rings as well.