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Technical Wheel/tire bounce - vibration

Discussion in 'Traditional Hot Rods' started by ace high, Jul 16, 2017.

  1. Pete Eastwood
    Joined: Jul 27, 2011
    Posts: 941

    Pete Eastwood
    Member
    from california

    Do the simplest thing first. Jack the car up & spin the wheels. If the tires are out of round, you will see it, & you will never get it to smooth out. Those tires are known for being out of round. You can have them trued. Eliminate this problem first, then go from there.
     
  2. ace high
    Joined: Dec 15, 2007
    Posts: 210

    ace high
    Member

    Did the test with a dial indicator and surprisingly for these tires, they ran true.
     
  3. You are the same guy who asked about caster adjustment? Without seeing the car in person, I think you have more going on in need of attention than just tires. How did you resolve everything discussed in the other thread?

    From memory the front axle was pretty flimsy for a start.
     
  4. ace high
    Joined: Dec 15, 2007
    Posts: 210

    ace high
    Member

    Almost all of the death wobble is gone. Fine tuned the caster and toe in . Still think my steering arms are bent too much. The effective length is too short. Separate from that, front tires vibrate badly after 60mph.
     
  5. Almost you say? Mmm. Well, little things can be magnified as speed/rpm increases.
     
  6. Remove your wheels and tires, then remove your Buick brake drums/hubs from the spindles and take them to a shop that will work with you to spin balance them. They can be set up on most spin balancers. Notice the rusty steel weight on this drum? Remove any you have on yours and check the balance. There may be more than one weight on your drums. See what the balancer says you need to balance the drum/hub assembly. Find more weights to use or make your own out of steel or lead. Be sure to include the two small bolts to attach them to the drum, drill and tap the drum to attach them. You can start heavier than what you need and fine tune the weight by removing material from the weight. I have multiple sets of drums so I have an assortment of weights that I use. My '32 pickup runs smooth with this combination and balancing method.
    [​IMG]
    Now for your tires, the easiest way to eliminate them as your problem is to find someone who has a similar size and bolt pattern that runs smooth and vibration free that you can swap them on to your car to see if the problem goes away. You could try bias or radials, because you just want to eliminate the tire/wheel combination as the problem.

    I'm betting on the Cokers being the problem based on their reputation for this issue.
     
  7. quicksilverart46
    Joined: Dec 7, 2016
    Posts: 460

    quicksilverart46
    Member





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  8. quicksilverart46
    Joined: Dec 7, 2016
    Posts: 460

    quicksilverart46
    Member

    Are they new or old original wheels? If they restored originals then you may have a bent wheel. I went thru this with original 16's on a '40 woodie. repainted and pinstriped all 5 wheels including the spare. re mounted the tires and suddenly had a vibration at 60mph. After spending a ton of money shaving the tires , then balancing, then re balancing on a deal that spins it on the car . then I tried the driveshaft re balance and finally a new shaft . It still vibrated. tried new bearings on rear axles and pinion and still vibrated. car was always smooth before even at 75 mph ! It turned out to be the damn spare tire wheel was bent and while doing the wheel painting and a new set of tires the bent one that I never knew I had mistakenly got put on the rear. I at first thought the tires were out of round and that led to all the other crap I tried ,and all for no improvement at all. All caused by just one bent wheel!


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    jeffd1988 likes this.
  9. jeffd1988
    Joined: Apr 12, 2016
    Posts: 537

    jeffd1988

    I would check those shocks and make sure those drums have weights that is were it is at one of the 2 mayby both. If tires are balance and alignment is right. Mayby check the rear as well of the same thing. And make sure your drive shaft is balanced and if you have a 2 price drive shaft check that center bearing. Mostly shocks and drums I'll be looking into

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  10. One more thing. When you use the early Ford hubs with the Buick drums, the whole assembly needs to be rebalanced. The existing weights probably will be off because the drums have to be turned with the new hubs for everything to run true.
     
  11. ceege
    Joined: Jul 4, 2017
    Posts: 204

    ceege
    Member
    from NW MT

    Wow, lots of advise. Careful interpretation will be your next obligation.
     
  12. 31pickemup
    Joined: Apr 9, 2006
    Posts: 1,272

    31pickemup
    Member

    You need a steering damper. It clamps to the steering rod and then to the frame. Mine 31 did the same thing and this helped a ton. It helps stabilize the front axle movement.


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  13. domingo
    Joined: Sep 22, 2012
    Posts: 78

    domingo
    Member
    from Lima, Peru

  14. alchemy
    Joined: Sep 27, 2002
    Posts: 15,759

    alchemy
    ALLIANCE MEMBER

    While you have the hubs and drums off the car getting checked for balance, also check the runout on the face of the hub. Pressing studs in and out of hubs can sometimes bend them. A little bit at the small diameter of the hub will be much worse at the large diameter of the tread.
     
  15. oldcars.acadia
    Joined: Jan 20, 2003
    Posts: 212

    oldcars.acadia
    Member

    You can mount the tire/wheel to the hub/drum and remove from the spindal and balance the entire assembly on a common spin balance machine. Mark a lug so the wheel can be remounted in the same position if removed. I do this with trailer tires as trailer brake assemblies are not balanced.
     
    29AVEE8 likes this.
  16. ace high
    Joined: Dec 15, 2007
    Posts: 210

    ace high
    Member

    I must have a bunch of unexperienced shops in my area. All the shops I've approached to balance the hub/drum/tire/wheel as an assy are telling me there no such machine and it can't be done.
     
  17. oldcars.acadia
    Joined: Jan 20, 2003
    Posts: 212

    oldcars.acadia
    Member

    Will work on most common spin balance machines. Just requires a little brain power!
     
  18. Come to the dark side and run radials.

    We have cookies...
     
    Last edited: Aug 10, 2017
  19. Luke S.
    Joined: Jun 3, 2005
    Posts: 180

    Luke S.
    Member
    from Ocala, Fl.

    Lots of useful suggestions here. I had a bounce issue from 55-60 mph or so. I swapped, changed, tried everything mentioned here, and more. Wheels, tires, air pressure. Shocks were brand new. Finally one day I took my front drums off the car and drove it. Was smooth as glass! Put the drums back on. Bounced again. I had aftermarket drums from NPD. F1 drums. I got some OEM Ford drums from a friend, and tried those Much Better! Still has a very slight bounce about 55 or so. But the average person wouldn't even notice it. I bought the drums from my friend, and haven't looked back since. 100% better! I had a friend recently had a similar issue. LF started bouncing. Got progressively worse. He rotated the wheel / tire on the drum. Clocked it... Like a totally different car. Problem solved. You may not experience the same results. But these are two fixes I have witnessed myself. Worth a shot. there's no magic, voodoo, etc. with any of this. It's all physics. Simple as that. Try one thing at a time, so you can single out an improvement from a specific change. Good luck.
     
  20. the-rodster
    Joined: Jul 2, 2003
    Posts: 6,665

    the-rodster
    Member


    "Clocked it" ? turned the wheel/tire 180 degrees on the drum?

    Rich
     
    Luke S. likes this.
  21. Luke S.
    Joined: Jun 3, 2005
    Posts: 180

    Luke S.
    Member
    from Ocala, Fl.

    Yes Rich. Just rotate the rim on the hub. Go one hole at a time. Might just be enough.

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  22. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,624

    dirty old man
    ALLIANCE MEMBER

    Haven't seen one in years, but Bear Alignment used to make a balance machine with which you pulled the tire, wheel, drum, and hub off together. Then you removed the inner and outer bearings and inner seal. mounted the assy. on the machine and spun it up. Did a first class job of balancing, but labor cost would be high now because of all the extra work involved.
    Haven't seen one of them in years and years, been at last 40-50 years since I've seen one. In this case, it might be worthwhile to check with all the old shops and old mechanics and try to find one of them. Even better than the on car spin ups because it had a sort of primitive electronic system built in.
     
  23. Old truck shops may have on-the-car balancing equipment around.
     
  24. coolbreeze1340
    Joined: Aug 18, 2009
    Posts: 1,342

    coolbreeze1340
    Member
    from Indiana

    Have you checked the radius rod/ hair pin connections at the frame? I fought an issue for a bit and finally found a hole that was oblong (frame wasn't sleeved) and caused a constant issue. Drilled out the hole, sleeved it, problem solved.
     
  25. oldcars.acadia
    Joined: Jan 20, 2003
    Posts: 212

    oldcars.acadia
    Member

    That is how I do it on the current balance machines. Extra time but works fine. Just use the wheel centering cones that will fit in the bearing races.
    Bob
     
    Last edited: Aug 12, 2017
    missysdad1 likes this.

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