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.
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.
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.
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. 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.
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! Sent from my iPhone using H.A.M.B.
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 Sent from my Z981 using The H.A.M.B. mobile app
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.
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. Sent from my iPhone using H.A.M.B.
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.
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.
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.
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.
Yes Rich. Just rotate the rim on the hub. Go one hole at a time. Might just be enough. Sent from my SM-G950U using The H.A.M.B. mobile app
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.
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.
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
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