Did you balance all 4.
Have you added air to the tires recently. I had a situation where the compressor tank had not been drained and the first thing that went into the tire was a load of water.
Were you able to watch when the tires were balanced to see if there were any wavy spots on the tire as it spun.
If you have access to a hoist or floor jack install the spare on each corner until the vibration goes away.
Get the spare balanced first looking for uneven spots on the tire.
Good luck
Chasing down a vibration can be very frustrating.
80 Miles per hour?
It may well be your speed control alert! Seriously though with my car now I had a shimmy at about 55 mph and when I talked to my old school front end guys they told me to experiment swapping my front tires with my backs. Did that with one and nothing, did the second and shimmy gone. Its a rim issue even though the tire was supposedly high speed balanced. I knew my front end and steering was good.
Making allowances for English not likely being your first language, am I correct to assume you have 4 new tires and had them balanced? Does the vibration just begin at 80 mph or can you feel it all the way up to 80? Does it get worse the faster you go? Are you feeling it on the steering wheel or on your ass in the seat? I agree with the guys who mentioned on car balancing is the best way to balance tires because it takes into account imperfections in drums etc. but it could also be a universal joint as was first mentioned. Rotating the tires to different locations as has been suggested, especially with radials, can also make the difference but if they are new I am inclined to think it is something else. Let us know what you find.
Rotate the front tires to the rear and the rears to the front. Drive it again. If the vibration moves to the rear of the car you'll know you have a tire or wheel issue. If the steering wheel still shakes it's something in the front end.
Do you have a spare wheel and tire that you can mount on the front and road test.
Transfer to the other side to see if vibration continues.
Isolate each wheel position.
Does any tire shop offer on car balancing?
I typed wrong, the car's front wheel shakes at speeds over 50 miles / hour. Has new tires that are balanced and new gas shock absorbers.
Hi Victor
do you feel the shaking on the steering wheel? Have someone check the play of the wheel vertically and horizontally to see if your hub nut could be loose or maybe you could have issues with a steering terminal?
-- Edited by Beau_SD_65 on Monday 8th of June 2020 09:59:07 AM
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Claudio
Trying to make some history with a '65 Acadian Beaumont SD south of the Equator line...