tire vibration?

My Dad's 1968 Chevrolet Impala 4 door hardtop has suffered from what I believe is tire vibration since we got it going 5 years ago. I know... sorry it is a Chevy and not a Buick, but it should be very similar to, say, a LeSabre. The vibration is the frequency of, and feels like a tire out of balance. Starts about 50 mph and is at the worst about 55 mph. Smooths out a bit by 65 but still noticeable. Can feel it in the whole car, with the steering column visibly bouncing up and down, and the antenna doing the hula. Installed 4 new Goodyear Viva 205/75R14 5 years ago to replace the bald and dry rotted bias plys, and have not tried other tires or wheels, and have not driven it with any tires but the Goodyears. Since then we have replaced front brake drums, all ball joints, shock absorbers, anti-roll bar links, lower control arm link bushings, and front wheel bearings, and also have rotated tires once, and balance checked twice (spin balance). Tie rods and control arm bushing seem solid. Car has had 2 wheel alignment. Nothing we have done has had any effect. Both places that did balancing did not find any excessive run out in wheels or tires. Hubs and axles appear to turn true, and the rear axle bearings seem solid. Car drives like a dream otherwise, and is totally smooth at 45 mph and under

Have read some reviews of Goodyear Viva tires with complaints of vibration that balancing does not cure, but before I pull the trigger and try another set of tires I want to be reasonably sure that it is the tires and not the car. Do hardtops tend to have issues similar to cowl shake like convertible do? Am I missing any thing?

 

If u had a spare the same as what is on the car, u could swap one tire at a time and maybe locate a problem tire.

 

The spare is the exact same Goodyear Viva purchased at the same time, so I might try that at each position. I was hoping to find some one with a set of wheels and tires that are known smooth runners that would let me borrow them for a bit. Good idea and thanks for the post.

 

Great Western Tire Store, a Goodyear dealer here in Rapid, has one. Wife has shingles so it will be awhile before I can get to it. Thanks for recommendation.

 

Have you checked the driveshaft u-joints/balance?

 

I have not checked the driveshaft balance. I have replaced the u-joints and that had no effect. Vibration is low frequency like you get with a tire out of balance, not high frequency like you get with driveshaft issues, but might be worth checking if the road force balance does not help.

 

My Caddy had a tire vibe that wouldn't go away with balancing. We road forced them and it made it better, but was still there. I'm not into snake oil, but the next thing we did was I had my tire guy at work check and road force them again, then I had him put in balance beads. Smooth as silk now.

 

Besides the road force balance recommendation, I would also be sure your balance is done with the lug adapter. If it was balanced by the hub, it will not balance right. Those old wheels, when they were made, were made with no guarantee that the center hub was machined to be perfectly concentric with the wheel; they were simply made to hold the center cap. New cars made today all have the center hub perfectly machined to be concentric; that's why tires are balanced by the hub (on new cars) and they balance just fine. It's only our lug holes that were machined to accurately locate the wheel and those wheels must be balanced by the lugs