[protovack]

ORIGINAL POST:
My car is brand new, about 200 miles so far. I have the 20" split spoke black wheels. There is a very noticeable vibration that occurs between 60-70mph. I feel it mostly in my seat. The steering wheel does not seem to be the source. The frequency is around 6-8 cycles per second. It makes a subtle "vu-vu-vu-vu-vu-vu-vu-vu" sound. It almost feels like the buffeting that happens when you have a window down, but more in the body of the vehicle. I can actually see the body of the car shaking. It happens every time I accelerate up to 60 mph. It's never happened below 60. It seems to go away if I get much beyond 70. It doesn't make a difference if I'm in V4 or V8. Going to manual and switching gears does not change it. It does not vary with the engine rpm--the vibration frequency is the same no matter what gear I am in, all that matters is the vehicle speed being between 60-70. What type of problem do you think I am dealing with here?

UPDATE:
See my latest reply down below, it did end up being a wheel/tire issue, but not an issue anybody was expecting...

[JoeCamaro444]

🤔 It sounds like the dreaded Torque converter issue that a portion of the 16s and 17s have had. I do not have first hand experience with it, but I have read a lot about it on here, where I have the A8 in my Camaro. I do not have the issue as of yet, and I hope I never do, but this is a known issue. There are multiple threads about it. Do a quick search using some key words, or standby and I bet someone puts a link to it here for you. Sorry to hear the news and best of luck with a quick resolution!

[quikag]

Scroll to the screen that shows remaining miles to empty and whether you are in V4 or V8 mode. If the vibration happens only in V4 mode, it’s the torque converter. They will try to flush method and if that doesn’t work they will replace it. I eventually got mine replaced and it’s been perfect since.

[protovack]

It doesn't seem to matter if I'm in V4 or V8 mode.

I've been doing a little research. I found multiple tire/wheel sites saying that a low frequency vibration between 60-70mph, felt in the seat is classic for rear tires being unbalanced. I'm surprised because aren't wheels balanced fresh at the factory? But then I read that rapid acceleration from standstill can twist the tire on the rim and ruin the previous balance job. I did do a couple pretty good runs during my test drive. The problem is I didn't do any highway cruising prior to that during the test drive, so I have no way of knowing whether the balance was off before I even drove it. The car I bought was test driven several times before me.

I would be SO happy if this was just a simple balance job and not a torque converter or transmission replacement

[LT Won]

Not to insult your intelligence by any means, but my wife had a similar issue, different car. Anyways, the fact that it’s at such a specific mph, have you had the dealer remove and rebalance all the wheels? If it were the TC or a mount/suspension issue I feel I would be more prevalent across your rate of speed. One of those rims may be slightly off or the tire wasn’t mounted correctly. Worth a shot to check out and a simple fix.

Edit: I only skimmed your most recent reply. Yeah, I’d check the balance job first.

[protovack]

Originally Posted by LT Won

Not to insult your intelligence by any means, but my wife had a similar issue, different car. Anyways, the fact that it’s at such a specific mph, have you had the dealer remove and rebalance all the wheels? If it were the TC or a mount/suspension issue I feel I would be more prevalent across your rate of speed. One of those rims may be slightly off or the tire wasn’t mounted correctly. Worth a shot to check out and a simple fix.

Edit: I only skimmed your most recent reply. Yeah, I’d check the balance job first.

Yep will do.

[Rock-It Man]

Being in a narrow MPH range, 60 to 70, this is most likely wheel balance or a defective tire.

That speed range is where the rotation rate of the wheel matches the natural frequency of the sprung wheel. Therefore, at that speed, the mass/spring system gets excited into vibration.

It's also true that tires are most likely to slip on the wheel soon after being installed. Also if under inflated. Before freaking out about the transmission, get the wheels road-force balanced.

[protovack]

Took it to the local dealer, test drove, the vibration was immediately obvious. Car was not riding smooth even below 55, and once in the 60-80mph range the tech instantly recognized the vibration. Probably wheels/tires. Went back and they said they would road force balance it. In the back of my mind I'm wondering, "How did the balance get so poor within 100 miles of leaving the lot brand new?" They do the balancing, and then tell me, it wasn't that far off. Did they actually adjust the balance? Yes, the manager "thinks so." Manager says the tech drove it afterwards and claimed it was "much better, barely anything there, the tires are thin and you're going to feel everything, don't expect it to be super smooth." Right. I take it out for a test before I go home. Vibration is still there exactly the same as before. Go back to the dealer, tell them nothing's changed and the manager tells me "It's a tire issue. You'll have to go to a tire shop." At that point I'm thinking, probably a good idea. I call up an independent tire shop 30 minutes away and make an appointment for that afternoon.

Go to the indie tire shop, tell them, I just got the car and needed to have it rebalanced at the dealer but it didn't fix anything. They are understanding and not surprised. They get the wheels off and use their balance machine. The balance is completely off on three out of four wheels. They tear off all the old weights and rebalance, using far less weight than the dealer used.The tech notices there is a circular strip of gouged metal on the inside surface of one of the 9.5" rear wheels. It's been rubbing on something. Asks his assistant "Hey, where did you pull this wheel from?"

"Front right."

"Aren't these supposed to be staggered?"

"Yea."

"Then why is the 9.5" wheel on the front?"

[checks all wheels against their locations again. Comes back to me.]

"Your wheels are all mixed up. Your rear left wheel was in the right front position and had the right front tire on it. And your right front wheel was in the back left with back left tire on it. The rear wheel that was in the front is gouged all the way around because it was rubbing on something. This explains the vibration and is the reason they couldn't balance at the dealer. You are going to have to get a new wheel from the dealer. We'll have to charge you for the services today but you'll probably be able to get refunded by the dealer because it was brand new. Make sure to take your receipt."

So they charge me $100 for their time which I was happy to pay, gave me a receipt with a detailed explanation of the issue. These guys were great. Before I left they asked me if I would show them how the NPP exhaust works and, that they loved the color (arctic blue metallic!) I drive home and the vibration is completely gone, rides smooth as butter. Not a huge surprise but I was pretty relieved.

[torqueaddict]

Well I'm glad you got it sorted out. I would have never guessed on the wheel mix-up. Given the dealer's misdiagnosis and its poor handling of the situation, I'd say it was them that screwed up. Good luck.

[protovack]

Went to the dealer today. They are ordering me a new wheel and refunding my expenses from the tire shop. They were apologetic but had no idea how the wheels got flipped, it must have come like that from the factory. This would be the first time I've ever heard of that happening. But it's also the first time I've owned a car with a staggered wheel set-up

[torqueaddict]

Nice that they are owning up to it and making it right. This is my first car with a staggered setup as well.