Wheels / Tires: 68 MPH vibration

[Hawkowner]

My Tale of woe!
Ever sense I purchased my 62 Hawk I have been chasing a 68 MPH vibiraton .
When I purchased the car it had very good almost new tires so I paid for a wheel balance.
Then I checked the date codes on the tires and my car buddies told me horror stories of tire failures of out dated tires on hearsay but actual experience so I bought new tires from the same company that did balance.
Tire company advised that wheels were not real shape or true. Vibiraton a little better but still bugging a guy that worked on truck tire vibiraton all over the country and not pleasant trying to run I 75
Bought new American RacerAluminun 6 in by 15 in wheels and had the new P215 / 70R Fireston tires installed.
Threshold speed increased slightly to 70 mph and not quite as intense.
Had all 4 wheels road force balanced 1 tire was broken down and match mounted 1 wheel was one ounce off .
Vibiration worse at 68 but lessens at 70.Vibiration comes in and out like turning on a switch.
Vib feels like it is in vertical plane not a dither or shimmy.Hood oil cans.
Verry tough to run I 75 at 68 MPH.
Any one had experience with brake drums being out of balance?
Vibiraton continues with clutch in an engine at Idle.
No harmonics like a drive shaft.
Manual steering no lost motion in steering king pins are tight new looking shocks.
Comments welcome

Hawkowner

[PackardV8]

Not the worst problem, but understandably annoying. Over the years I've seen specific road vibrations caused by:
1. Brake drums
2. Bent axles
3. Center carrier bearing (your Hawk doesn't have one)
4. Clutch/pressure plate/flywheel
5. Engine balance
6. Worn motor/tranny mounts
7. Failing tranny bearings
8. Miasaligned bell housing

Jack Vines

[bezhawk]

My first thought was a bent axle.

[Ron Dame]

More likely a bent axle or bad U joint, but I had a severe vibration on my truck for years that I could not cure. I finally bought a Harbor Freight motorcycle tire balancer and found my drums were badly off, one taking three and a half ounces to balance. It's been smooth since.

[bezhawk]

Check your drums for telltale signs of a balance weight that has come off. They were spot welded on, and you may be able to see where one may have broken loose

[Hawkowner]

I am leaning toward brake drums looking for spin balance on the car!

[RadioRoy]

I am leaning toward brake drums looking for spin balance on the car!

If you re-balance the wheel to accommodate an out of balance drum, that wheel can only be used on that drum with that same clocking. Better to balance the drums independent of the wheel.

[JoeHall]

The smoothest driving experience I can ever recall in a Stude was when I had a set of tires mounted on the 62GT in the late 1980s, at a Western Auto Store in 29 Palms, CA. They spun balanced the tires while mounted on the car, and used a tire shaver mounted down inside the floor, to insure each tire was perfectly round. I believe that's the way all good shops used to do it back in the day. But have not seen nor heard of such a shop since. For the first 10,00 miles or so on those tires, the car was as smooth as a modern car.

Neither before nor since that experience, have I had a smooth Hawk. They all seem to vibrate around 68-72 MPH. I have learned to live with it, and either speed up or slow down a bit; on either side of the vibration, its fairly smooth, but not, "modern car" smooth. I know its not the front drums, because I have ran front discs exclusively for over 10 years now. I believe another tire store like that Western Auto could fix it easily, but they simply do not exist anymore.

About all I can say is, good luck with that

[christophe]

This guy also had a problem around 68 mph.

https://www.youtube.com/watch?v=DQfFS-mEOGE

Apparently, he solved it with Dynabeads.

[Hawkowner]

I have seen this stuff tried on truck tires with no success. They used to make houla hoops with with ball bearings and fluid that clipped on the rims did not work.

[jclary]

I once owned a 62 GT that had a terrible vibration. I lived with it for over a year while addressing other issues. Finally, when it came time to buy new tires, I gave it the long overdue attention it deserved. The tire store was very understanding, and took getting the vibration out as a challenge. They had a policy that customers could not come into the shop where the work was being done. (Sign read because of insurance restrictions),so I watched through the waiting room window. Several different sets of tires were mounted, balanced, and I was told it was good to go. Each time, I would take it out for a test drive, and the vibration was always still there. Mainly, it was always worse at highway cruising speed.

Back at the tire store, the guys even pulled out their old "on the car" balancer that had been replaced with the computer balancer. In fact, they would also use an even more ancient bubble balancer to double check. They became so familiar with me, they invited me to stay in the work area so I could observe how they were doing their work. I believe we were on the fourth or fifth attempt, when I took a moment to spin the front brake drum while the wheel was off. I was "stunned" at what I observed. Using a "sight reference" of a stationary part of the front underside of the car, it was clear as a bell that the brake drum was out of round!

Pointing it out to the manager, both of us, almost simultaneously, began to apologize to the other for not noticing it before. That explained the vibration, and the hint of a front fender repair should have been a clue. Turns out, that the ninety year old former owner (great guy) had outlived his driving capabilities. At some point, he had hit something that damaged the passenger side brake drum/hub. I had purchased the car from his estate. We installed the tires, I drove home (vibrating) and exchanged that brake drum for one on a "parts car." "Problem solved!"

I suggest putting a dial indicator on your brake drums and check for run-out. While many of us, think of brake drums as one of the toughest components on a vehicle, I can confidently say, they can warp!

[Hawkowner]

You have given me hope I am getting ready to go north and I am putting the car jack stands.considering going to disc brakes even though one very good write up said he had no better luck with disc .
I am looking for a location that tries the tires. I see there companies that shave tires so you don't need to replace all four at once,

[altair]

Just to eliminate the possibility, rotate the drive shaft 1/2 a turn. If it is a front wheel/tire you should feel the vibration on the steering wheel.