I'm beaten, I admit it

The shake in my 8 is like a gremlin, it moves, it occurs at different speed, I just dont know. Tomorrow I am making an appointment with the area suspension expert and let him fight with it. He is not cheap but he is dang good, old school confirmed with the modern gee whiz stuff. (He collects Studebakers so he has to be cool)

Just to make my life more difficult, I took my 8 to the local tire shop, had them balance the tires, seemed to solve the problem then it came back harder... I pulled the tires and was looking at the suspension and my daughter noticed they used the stupid stick on weights and the passanger side tire was missing it. Took them and they fixed it for free and put it on the car and wow, it seemed fixed but it is still there, just between 35-45 MPH. Last year the shake was at highway speed in sweeping left turns.

Here is a list of the things I have done to try to solve it

It has new ball joints and tie rods, all good
aligned
tires balanced
New wheel bearings
new rotors and calipers
new struts
new bushings
checked the subframe mounting points
It could benefit from new sway bar bushings but I dont think that is it
With just the money I dumped in it this and last year I should be driving it all summer

I will let every one know what they find out, make your guess now

Had that happen to my TR6. It was the old redline tires. The plys were separating.

I had a harmonic vibe in my GT6, it about drove me coo-coo trying to find the problem. This car had a totally new suspension, every part front and rear was new including the gearbox.

EXCEPT the propshaft! In the end, the propshaft was off-balance, causing vibrations at about 40ish MPH (regardless of the gear I was in).

I discovered this while under the car one day: I could see an area of new paint on the propshaft where a counterbalance weight once was. So, I dropped the propshaft and took it to a machine shop to have it balanced, problem cured.

Cost about $50 to have it balanced. It was way out of balance. Strange.

YMMV, please let us know what happens.

Another day in LBC land . . .

Maybe just drive it faster?

Hi... Curious if you've had your tires "road force" balanced... (go here https://www.gsp9700.com/pub/features/how.cfm)

Twice I've developed vibration problems with a Fiat X1/9 that normal balancing didn't cure, but they were successfully diagnosed during "road force balancing". Once it was an ever so slightly bent wheel and the other time it was internal tire damage.

Find a garage that uses one of those Hunter machines...

Yea, what he said.

I'll bet a fried chicken tv dinner that you have tire issues.

Have it on my van, Goodyears, 1 year old, less than 10000 miles, they go thump thump,

Rotate their positions on the vehicle, and it changes.

I was thinking the tires, they are old (7 years but still look good) I am going to go get new tires right now (well this week end)

I agree with Jim W. about the Hunter 9700 balancing equipment. I own a Miata, and if the balance on the rear tires aren't pretty near perfect, there is the dreaded vibration. It usually occurs at 65 mph with a minor tremble at about 30 mph. The Hunter will find out where the problem lies, and is capable of balancing in grams, rather then the usual ounces.

It's worth a shot. It worked for me on my Miata.

This was suggested before, but I'm still wondering ...

Did you ever actually check each wheel (wheel, not tire) for being bent and/or out of true?

Tom

I took the wheels to a speed shop where they checked for "true" on the rims and they said event though the rims (Panasports) are poorly factory balanced compared to moderns wheels they were on and had no cracks. I was worried about that (or maybe hoping for an excuse to go to 15 or 16)

Any time you go wider or change the offset on rims, You need to balance with weights inner and outer. Not just inner, so unless you have a wide lip and minimal offset you need to put weights on the outer lip..


And roadforce balance is good, as it checks the entire, wheel/tire assembly mounted on the car, the way it is driven..

martx-5 said:

I agree with Jim W. about the Hunter 9700 balancing equipment. I own a Miata, and if the balance on the rear tires aren't pretty near perfect, there is the dreaded vibration. It usually occurs at 65 mph with a minor tremble at about 30 mph. The Hunter will find out where the problem lies, and is capable of balancing in grams, rather then the usual ounces.

It's worth a shot. It worked for me on my Miata.

Click to expand...

The Ninety-Seven Hundo (or just Hundo) will solve all of yer woes. I was a go-to guy for ride problems for a couple of years at D******t Tire. The thing is a slow clunky pig to operate and a PIA if you were in a hurry, but it will find problems. Give it a whirl. God I hate Cooper tires...

I had this same issue on my white TR8 coupe. I changed wheel bearings, had all new brakes, tierod ends and ball joints. It turned out to be tire pressure and one tire that needed more weights than the other three tires. I put that one in the rear checked tire pressures cold and hot and this were fine. I had Shelby Magnesium 8 Spoke rims (13x6) with a 185/70/13 tire. You might have to do the same by moving the worst tire to the rear with the balancing weights and playing with tire pressures.

The speed shop took the tires off and stripped the weights on the rims and balanced them and "trued" them to make sure they were not bent. with out weights they said they were now well balanced from the factory

Isn't there a shop near you that can do an alignment with you sitting in the car?

PATR8 said:

The speed shop took the tires off and stripped the weights on the rims and balanced them and "trued" them to make sure they were not bent. with out weights they said they were now well balanced from the factory

Click to expand...

Interesting - I'd always heard that wheels couldn't be "trued" at all, as that weakens the steel. Did they just "true" the outer edges of the wheels (the part that can get bent when mounting/dismounting a tire?

Edit: we're not talking "balance" - we're talking "true" (untrue = wheel itself is bent at the hub).

The test I used to determine my wheels were "out of true" was just to spin each wheel while on the car, brace my arm, hold a pencil pointing toward the side of the wheel, and see if the wheel moves in and out ("wobbles") from the pencil tip. Three of my four wheels were wobbling; new wheels completely eliminated the vibration problem.

Wonder if you'd notice any change in the vibration if you test-mounted four brand new wheels with brand new (balanced) tires, then take it for a drive. At least that would show if your current wheels have anything to do with the problem.

Tom

They have a machine that looks like a balancer that is more just a laser that as the wheel spins it measures the rim for "true-ness" Doesn't look real high tech but as the tire spins it shows you in 3D where the tire is bent and how far. They say they use it mostly for wire wheels beacuse they do adjustments on them

Tires, Tires. Tires, you said they were 7 years old. That's 7 winter seasons of sitting on concrete 24/7 for 3 or 4 months at a time. That of course assumes that you do not drive in winter weather. Flat spots, rubber hardens, they may look fine.

Good Luck

When I started this one season tear down of my 6 years ago.A young gent near me was recommended to true the stock wheels. He did what he could for four of them. The worst one is now my spare. Still has "use this for spare" on it.