[C2] Shake at 55 mph?
06-21-2022, 07:05 PM
#1
Shake at 55 mph?
My '64 convertible has a distinct shake at 55 mph. Starts around 52 and disappears around 58. I have replaced 2 rims, 6 different tires and two shops have checked tire balance. Today I rotated my extra tire ( won't fit in the spare carrier) all around the car so I drove it 5 times with a tire replaced each time with the one I took off on the prior trip. No change at all no matter what tires are on the car. What can cause a shake at 55 besides an out of balance tire?
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06-21-2022, 07:20 PM
#3
Ted, Car was restored and front end components all have less than 3000 miles on them. Springs, shocks, tie rod ends , wheel bearings etc. all are new. Maybe one is bad but still new.
06-21-2022, 07:31 PM
#4
Well, if everything has been rebuilt, all should be good in that realm. I would still check the wheel bearings for excessive play just to make sure something didn't come loose. I say that, because I saw this happen many years ago on a car and a pretty bad front end shake was the result.
Just food for thought.
Ted
Just food for thought.
Ted
06-21-2022, 07:57 PM
#5
Burning Brakes
Is you shake under acceleration? Deceleration? Steady cruise? Clutch in? 55 mph in 3rd gear? Or only 4th gear?
06-21-2022, 08:16 PM
#7
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Chief, you haven't specified where you feel the shake..... steering wheel, seat of your pants, just over the entire car??
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06-21-2022, 10:26 PM
#10
The shake is all over and happens when steady cruising in 4th gear, I have not tried to run at 55 in 3rd. Driveshaft looks new but I have no idea how it or the u-joints were installed or in what position.
06-21-2022, 11:00 PM
#11
Team Owner
Have the drive shaft balanced.
06-22-2022, 07:04 AM
#13
Melting Slicks
What brand are they? COKER tires have a bad rep for being out of round. I had a set of GOODYEAR SR-A's on my truck from SAMS CLUB that could not be balanced, they do not use the road force machine.
06-22-2022, 08:07 AM
#14
Race Director
Are the shocks new? I remember as a kid my 64 Plymouth had a bad vibration at highway speed (probably tire tramp) that went away when I put new shocks on it. It usually is also a symptom of less than good tire balance but the shocks were the main contributor in my case.
06-22-2022, 07:02 PM
#15
Drifting
Chief, How about getting up to where it shakes, and putting it in neutral and let it coast. Does it still shake or does the shake go away?
Gerry
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06-22-2022, 10:00 PM
#16
Drifting
Are the shocks new? I remember as a kid my 64 Plymouth had a bad vibration at highway speed (probably tire tramp) that went away when I put new shocks on it. It usually is also a symptom of less than good tire balance but the shocks were the main contributor in my case.
The OP states that the vibration starts at 52 mph and goes away at 58 mph. Doesn't vibration from tire imbalance get worse as speed increases?
Gerry
06-22-2022, 10:10 PM
#17
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There must be more to this. I can't understand how worn shocks could be the main contributor to a vibration caused by tire imbalance.
The OP states that the vibration starts at 52 mph and goes away at 58 mph. Doesn't vibration from tire imbalance get worse as speed increases?
Gerry
The OP states that the vibration starts at 52 mph and goes away at 58 mph. Doesn't vibration from tire imbalance get worse as speed increases?
Gerry
Once the rotational rate of the imbalance mass exceeds the resonant frequency of the suspension, the shaking diminishes dramatically.
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06-22-2022, 10:14 PM
#18
Drifting
06-23-2022, 06:54 AM
#19
06-23-2022, 07:33 AM
#20
My plan:
Ok, To answer some questions, the shocks are almost new, tires are cooper 205x75R15, I have about ruled out tire balance as I have had 2 shops check the balance and have 2 new rims and have rotated 6 tires and wheels thru the car with no difference. I did get a PM from a gentleman who chased the exact same vibration for 10 years and finally had the driveshaft balanced. I am going to have the car aligned and then have the driveshaft balanced. Thanks for all the help guys.