Dad's '52 Super Has a 55mph+ shimmy......

[BuickNut]

Hi, my dad's '52 Buick Super 4 door shimmies around 55 mph or faster. You really feel it through the steering wheel as well as the entire car. It has newer bias ply tires (less than 100 miles on them - balanced when put on the rims), my buddy did a check on the front end before the tires were mounted 4 years ago, so supposedly the front suspension is ok. I did the 'ol basic "bounce test" to see all 4 shocks were ok, and it stops before the 2nd bounce after I stop bouncing it. The car sits in his garage during that time, and is not on jack stands to keep it off the tires. Might this just be flat spots on the tires, and if so - what might be the number of miles needed to get the flats out ? I know already though - shame on my pop for not putting more miles on it........ Thanks for your advice.

[our51super]

I would be inclined to say that it may still be a balancing problem if you only feel it at higher speeds (55+ MPH). I have had great luck with having our tires/wheels "road forced". This is a balancing process where abtou 700 lbs of force is applied to the tire as it's being balanced to simulate the road force. It does a fantastic job of getting rid of the front end vibrations.<P>Good luck.

[Guest]

Jack the front of the car up and grab the tire. See if you can rock it back and fourth. If it rocks it is a suspension or wheel bearing problem.

[Guest]

You might try checking the driveshaft and U-joints. I came across a similar problem on my 65 Skylark GS.

[BuickNut]

Thanks gents.....all very logical possibilities as to the root cause, I'll give the car a check over in those areas.

[Guest]

BuickNut:<P>I would not eliminate the tires simply because they are new. Indeed, these bias ply tires may have sit in a warehouse for years or may be reproduction tires of dubious manufacturing control.<P>My experience with shimmys in the speed range you are talking about is that balancing rarely has any effect. At 55 mph, the loads due to imbalance are simply too small. Instead, check the runout on the tires and/or wheels. Unfortunately, tires can have internal flaws, like delaminations, that cannot be seen, but as the tire rolls, it puts strong loads into the suspension. If the runout is low (less than 1/16 in), you might try mounting some other tires just to see what happens.<P>Good luck!<BR>Bill.