Re: 1995 Corvette Coupe LT-1
Thread Starter
Heel & Toe
Joined: Feb 2021
Posts: 15
Likes: 1
Re: 1995 Corvette Coupe LT-1
Hi everyone, I'm new to this site so please be patient with me if I make some mistakes.
I have a problem with my 1995 Corvette. The car vibrates above 70mph the faster U go the worst it gets, drives fine under that speed. Work done so far- new tires force balanced 4 times, rims trued in by a wheel shop, driveshaft trued w/new U-Joints, 4-wheel alignment twice, new tie rod ends installed. Car only has 61K actual miles looks like new inside and out, it's an unrestored survivor. 4 garages and 3 tire shops still can't locate the problem, anyone out there have any ideas what to check next? Car has never been wrecked or raced/abused. P.S. My email is barryinaz@outlook.com Thanks
I have a problem with my 1995 Corvette. The car vibrates above 70mph the faster U go the worst it gets, drives fine under that speed. Work done so far- new tires force balanced 4 times, rims trued in by a wheel shop, driveshaft trued w/new U-Joints, 4-wheel alignment twice, new tie rod ends installed. Car only has 61K actual miles looks like new inside and out, it's an unrestored survivor. 4 garages and 3 tire shops still can't locate the problem, anyone out there have any ideas what to check next? Car has never been wrecked or raced/abused. P.S. My email is barryinaz@outlook.com Thanks
Last edited by Barry Lerer; Feb 20, 2021 at 11:02 AM.
Drifting
Joined: Feb 2017
Posts: 1,274
Likes: 399
From: Tacoma WA
2024 C4 of the Year Finalist - Unmodified
A4 or 6 speed? Does the vibration change at all if you put it in neutral at speed?
It sure sounds like the shops have gone over everything that would create that type of vibration! It does seem strange that there is not even a slight indication of the issue under the 70mph trigger. Normally if it was due to a rotating component, (engine, drive train, tire/wheel, etc) it would show up slightly below that trigger point. It almost sounds like the “speed wobble” one gets on a motorcycle that is not tracking perfectly but the alignments would have caught that.
I will be watching to see what finally solves this issue.
It sure sounds like the shops have gone over everything that would create that type of vibration! It does seem strange that there is not even a slight indication of the issue under the 70mph trigger. Normally if it was due to a rotating component, (engine, drive train, tire/wheel, etc) it would show up slightly below that trigger point. It almost sounds like the “speed wobble” one gets on a motorcycle that is not tracking perfectly but the alignments would have caught that.
I will be watching to see what finally solves this issue.
Le Mans Master
Joined: Oct 2004
Posts: 7,706
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From: Everett WA
C4 of Year Finalist (appearance mods) 2019
Here is a suggestion just for your consideration.
Get your car on a highway with some friends in another car. Get your C4 going to the point where you feel the vibration and have them video each of your 4 wheels as your going along. They will have to slowly pass you on your left and pass you on your right. It would be interesting to see if you can catch one of the 4 corners vibrating.
Get your car on a highway with some friends in another car. Get your C4 going to the point where you feel the vibration and have them video each of your 4 wheels as your going along. They will have to slowly pass you on your left and pass you on your right. It would be interesting to see if you can catch one of the 4 corners vibrating.
Le Mans Master
Joined: Jul 2000
Posts: 7,639
Likes: 326
From: Greenville SC
How long has it done this, did you make any changes right before this started?
I would say it is a wheel out of balance, except you said you had them "force" balanced, which I think you mean Road Force balanced on a Hunter, which should do the trick.
I had similar issue with new tires, even though balanced twice, then I had a Road Force balance that fixed it. The vibration was violent, felt like the car would shake apart.
Check the wheel bearings, any play in them, any roaring sound, or any other odd sounds?
I would say it is a wheel out of balance, except you said you had them "force" balanced, which I think you mean Road Force balanced on a Hunter, which should do the trick.
I had similar issue with new tires, even though balanced twice, then I had a Road Force balance that fixed it. The vibration was violent, felt like the car would shake apart.
Check the wheel bearings, any play in them, any roaring sound, or any other odd sounds?
Thread Starter
Heel & Toe
Joined: Feb 2021
Posts: 15
Likes: 1
1995 Base Coupe high speed vibration.
A4 or 6 speed? Does the vibration change at all if you put it in neutral at speed?
It sure sounds like the shops have gone over everything that would create that type of vibration! It does seem strange that there is not even a slight indication of the issue under the 70mph trigger. Normally if it was due to a rotating component, (engine, drive train, tire/wheel, etc) it would show up slightly below that trigger point. It almost sounds like the “speed wobble” one gets on a motorcycle that is not tracking perfectly but the alignments would have caught that.
I will be watching to see what finally solves this issue.
It sure sounds like the shops have gone over everything that would create that type of vibration! It does seem strange that there is not even a slight indication of the issue under the 70mph trigger. Normally if it was due to a rotating component, (engine, drive train, tire/wheel, etc) it would show up slightly below that trigger point. It almost sounds like the “speed wobble” one gets on a motorcycle that is not tracking perfectly but the alignments would have caught that.
I will be watching to see what finally solves this issue.
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Thread Starter
Heel & Toe
Joined: Feb 2021
Posts: 15
Likes: 1
The car had old tires with good tread on it when I bought it, took it to a Vette shop and they said the tires had flat spots and should be changed out, when I first drove the car on the freeway I couldn't take it over 50mph, after buying the new Nitto 555's it would go up to 70mph with no vibration and even with all the work I've done it still won't go over 70mph without vibrating, and the faster I go the worst it gets, the whole car vibrates, can't really tell if it's coming from the front or rear. At 80mph everything in the rear view mirror is a blur.
Thread Starter
Heel & Toe
Joined: Feb 2021
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The car has Bilstein shocks all the way around and they are all in real good working condition, I don't think it's "Basket-Balling". If you push down on the fenders when it's sitting still if barely drops down an inch. I've driven it on asphalt and concrete pavements both smooth and rough surfaces and that makes not difference either.
Burning Brakes
Joined: Jan 2019
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From: Park City, TN
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For me when I had something similar in my 96, it was a slightly warped rotor. But I also felt it in my brake pedal at speed.
Turning the rotor did not fix it. New ones did.
Turning the rotor did not fix it. New ones did.
Drifting
Joined: Apr 2020
Posts: 1,925
Likes: 610
From: Orange, CA
Congrats, there's the problem. The Nitto 555 G2 tires are notorious for vibrating horrendously at freeway speed when out of round until they're heated up sufficiently to return to round. They can go out of round just by leaving the car sitting overnight, or parked during a 9-hour workday.
I know, I own a set, and another user here did too (and was told by Nitto that the solution was to leave your car on jackstands whenever you aren't driving it).
I know, I own a set, and another user here did too (and was told by Nitto that the solution was to leave your car on jackstands whenever you aren't driving it).
Drifting
Joined: Feb 2017
Posts: 1,274
Likes: 399
From: Tacoma WA
2024 C4 of the Year Finalist - Unmodified
I agree with Nitto tires exhibiting the conditions Nomake Wan states since they did exactly that on my 92. However since you tried a different wheel and tire set with the same results there is something else contributing to this problem.
Try Mr. Peabody’s suggestion of having someone in an adjacent car video tape each wheel at speed and you may find the issue.
Try Mr. Peabody’s suggestion of having someone in an adjacent car video tape each wheel at speed and you may find the issue.
Drifting
Joined: Apr 2020
Posts: 1,925
Likes: 610
From: Orange, CA
Did he actually try different tires that weren't Nitto 555 G2s? It's hard to tell from his post if by "different tires" he meant "different from the flat-spotted ones that were on it originally" or "different from the Nitto 555 G2s I bought."
Melting Slicks
Joined: Feb 2015
Posts: 2,069
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From: Park Ridge New Jersey
Congrats, there's the problem. The Nitto 555 G2 tires are notorious for vibrating horrendously at freeway speed when out of round until they're heated up sufficiently to return to round. They can go out of round just by leaving the car sitting overnight, or parked during a 9-hour workday.
I know, I own a set, and another user here did too (and was told by Nitto that the solution was to leave your car on jackstands whenever you aren't driving it).
I know, I own a set, and another user here did too (and was told by Nitto that the solution was to leave your car on jackstands whenever you aren't driving it).
Thread Starter
Heel & Toe
Joined: Feb 2021
Posts: 15
Likes: 1
When I got the car the tires looked great treadwise but they only had 20psi in them, took car to Vette shop he said the front ones were old and all four had bad flat spots in them, bought new Nitto 555's they added an additional 20mph to the speed when the vibration starts. It now vibrates at 70 instead of 50. I bought the new Nittos in July in Phx. I assure you at freeway speeds they get plenty hot. It doesn't matter if I drive it 10 miles or 50 miles the car vibrates over 70 and you can't drive out of it, the faster I go the worst it gets, I've had the tires balanced on Hunter machines in 3 different shops. My service advisor put his Goodyears on it and no improvement. I think the U-Joints on one of the half-shafts are bad, had the driveshaft done and again no improvement. Wheel bearings are all good, shocks are all good, torque converter and flex plate are good, trans is tight and noise free.
Drifting
Joined: Apr 2020
Posts: 1,925
Likes: 610
From: Orange, CA
Okay, that's the important part. 555 G2s are still notorious for vibrating badly over 60 MPH or so, but at least that probably rules out the tire as the majority cause of your specific issue.
If wheel and tire balance isn't the problem, it does make me wonder if there's an issue with your brakes. I wonder if your fronts are sticking ever-so-slightly. After a decent drive (say, 30 minutes with plenty of brake use), does the car roll freely? If you jack up the front of the car right after concluding a long drive, can you freely spin the front wheels?
If wheel and tire balance isn't the problem, it does make me wonder if there's an issue with your brakes. I wonder if your fronts are sticking ever-so-slightly. After a decent drive (say, 30 minutes with plenty of brake use), does the car roll freely? If you jack up the front of the car right after concluding a long drive, can you freely spin the front wheels?
Drifting
Joined: Feb 2017
Posts: 1,274
Likes: 399
From: Tacoma WA
2024 C4 of the Year Finalist - Unmodified
Take a Go-Pro camera and figure out how to mount it so it captures a video of the drive shaft, then the half shafts to see if they are causing the vibration. I doubt that it is u-joints since if they were bad enough to create the vibrations you are experiencing I would think they would have been diagnosed during the troubleshooting your mechanics performed.
Good luck!
Good luck!
