High speed wheel hop

Hoping to get some help or ideas on what might be the problem with my 360 spider. I bought my car several years back, it came with 430 wheels which I really like. I bought some spacers from a local shop about a year ago and I felt the look was really perfect. So I noticed about 3-4 months ago while on the freeway, I had the opportunity to drive fast and noticed a left wheel hop noise and could feel a vibration so I slowed down and everything resolved. Over the next few months this wheel hop seems to be getting much worse. The car is rock solid up to 90 mph then all hell breaks loose. I can hear what sounds like a violent wheel hop and can feel it in the front end. Oddly not so much in the steering wheel.

First thing I did was replaced my 7 year old tires to Michelin PS2. Did not solve my problem. So I removed the spacers and re-installed the break disc fixing screws. Still have the wheel hop. I inspected all suspension components for play or damage, and the struts don't appear to be leaking any oil. I am just stumped. The shop that installed my new tires did not notice an obvious bent rim. The wheels appear perfect upon visual inspection on outer and inner rims. Not sure where to go from here except try a new set of wheels possibly if I can find a set to borrow? I did take a video with my iPhone that I will try to upload. Please help.
Thanks,
Steve

 

Not sure if this video helps but I will include it. I jacked the car just enough so that I could spin the wheel and it seems just a bit out of round. Why only at 90 mph?
https://www.youtube.com/watch?v=j4bOf2eYylk

 

Take her to a good wheel shop and let them see what is wrong. May be out of round, and your spacers may not be symmetrical around the bolt holes. A good shop can pinpoint the problem and remedy. May be something as simple as balancing the wheel and spacer as a unit by spinning it up to speed.

 

Had a similar problem after I put CS rim on my 360 with Michelin PS2s.
Mine was a vibration which set in a 75mph.

No amount of static or "off car" balancing would not cure it.

But a shop in Naples Fl (Naples motor Sports) took on the task and cured it by taking the car to a shop with an on car balancer.

 

Thanks guys. I will start looking for a local shop that might be able to solve my problem. I will start by trying to balance at high speed and see if that solves my problem.