High speed vibrations Options

[Coligion]

My car just hit 96k miles, but this high speed vibration issue has always been a problem. When going over 55 mph, I'll get a ton of vibration from the steering wheel. I do have aftermarket wheels/tires. When I first bouht the wheels, I did not have centering rings and believed that would solve the problem. No dice. Even after getting the correct sized rings the car still vibrates. Before getting the rings, I did have the alignment and the wheels balanced. I wouldn't think inserting plastic hub-rings--in the center of wheel--could offset the balance, right? The shock/struts are relatively new, so it couldn't be that. Also, the car had this vibration problem even with the original wheels....Any helpful advice is appreciated.

[Coligion]

I've lost count of how many times I've aligned the car in the past three years. I've had an ongoing problem with the car wanting to pull to the right, so it's been aligned by a lot of different places in hopes of resolving the issue. I'm sure it could be related to alignment, but I have spent a great deal of time trying to get that right.

VieT9sD, what you're describing does happen to me on the highway. The car will have moments when it's quite smooth and other times it's very shaky and vibrational. Like you said, it seems to depend a lot on the road. However, more often than not, it's almost always not smooth, so i can't quite attribute all of my problems to the road surface.

I still find it interesting that these wheel vibration issues existed with the stock wheels. That makes me think it's something suspension based, but what exactly I don't know....Like I said in my first post, do you think added in the centering rings could mess up my balanced tires?