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Discussion Starter #1
Hi everyone, I bought a new 2018 Volt a few months ago now, and I'm having an issue that I am not sure how to resolve at this point.

I noticed almost immediately that there was a pretty significant side-to-side wobble that appeared around 35 mph and continued up to 50+ mph with decreasing severity. It must come from at least a couple wheels, because it's there ~1/2 the time, and changes after taking corners, for example (so alignment of the wheels matters).

I took it back to the dealer, and they told me something about potential flat spots on the tire, filled the tires up to a higher pressure, and told me to wait until the car had 500 miles on it because sometimes issues work themselves out.

I was in the process of moving, so I waited to take it to the dealer where I moved (the problem never went away), and the first time they tried balancing and rotating the tires. That didn't fix it. I brought it back and they had the shop foreman ride with me. He felt it, and suggested they check the runout of the wheels. In the end they just road force balanced it and said "that would have picked up anything, and it was fine" and gave it back to me. Still didn't fix it. I brought it back to them for the third visit (fourth total, including the original dealer). They kept it for almost a week and measured the vibrations while driving it, sent the results to Chevy, and told me Chevy said the measurements were within specs and to stop working on it, so they couldn't do anything else...

I'm not sure if they only drove it up and down the road once and happened to not catch the wobble (the guy said "I did feel what you're talking about, but I drove a new Volt and it did the same thing"), but I downloaded a simple accelerometer app for my phone, set it on the floor below my legs, and measured the x, y, z acceleration at 35 mph myself as I drove down a back road. Y and z were just random, from bumps in the road, but there is a VERY clear oscillation in the x direction (larger than the bumps on the road) that came and went after I took gradual curves. It happens at 7.7 Hz, and is about +/- 0.02-0.03g.

So my real question is, how would you suggest I proceed? I'm not sure at this point, since Chevy thinks it measured the vibration, and said they can't work on it anymore. On a side note, if you have any suggestions for what the cause of the wobble may be, I would be interested to hear your thoughts too.

Thanks!
 

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1) I'm 64, and have never heard of a driving condition referred to as a "wobble", unless in reference to a wheel that's bent. I'd like to hear more about the exact FEEL of the "wobble".

2) You never mention the word "alignment." Has the car been aligned, and does the printout show clearly that all specs are within the "green" zone? If not, insist on it. The printout should clearly show before and after.

3) Where are you located? If you add this to your signature, maybe someone near you can assist, either directly, or can point you to the best dealer/FE shop in your area.

Something's not right here...
 

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OK, this might be a crazy thought, but could it possibly be a problem with the Lane Keep Assist (LKA)? That system enables at 37mph.
 

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Discussion Starter #4
Thanks for the replies!

I haven't ever felt anything like this before either. Not the same as wheels out of balance. It's a straight side to side, left-right, motion. Maybe "shimmy" would be a good word? It's a oscillation, and the frequency is exactly what it should be for the size of the tires/speed. My phone confirmed the side to side feeling, since the way I had it positioned the "x" direction was left-right, "y" was front-back, and "z" was up-down (towards the sky/ground), and all of the oscillation was in the x direction. As far as I know, they didn't perform an alignment (didn't tell me anyway). Once I decide exactly my plan and go back I will ask about this, thanks for the suggestion. As for my location, I'm in the Knoxville, TN area now and I took it to Beaty Chevy (and I'll look into editing the signature!).

As for the lane keep assist, I don't have that! So it's probably a good suggestion, but not what's going on in this case.
 

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As for the lane keep assist, I don't have that! So it's probably a good suggestion, but not what's going on in this case.
LOL...I guess it's safe to rule out an LKA issue then!

pianocaddie suggested confirming the alignment. That makes a ton of sense to me...could be a problem with the toe-in or something. Hope you get this sorted out!
 

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I drive a TR7 that has manual steering and some have "wheel wobble" felt through the steering wheel and can be caused by a large number of things and until you hit on it can be difficult to diagnose and get rid of. New cars with their suspension geometry usually don't have this (or are less sensitive) but here goes: Tires have flat spot or are out of round. Tires can be shaved but you need special equipment that is not usually found in most garages these days, wheels out of balance (some have wheels balanced on cars to fix), the wheels are hub centric (Volts are lug centric so not likely this), worn/loose ball joint, tie rod, inner tie rod, steering rack internals, biasing of steering shaft into steering rack, steering shaft universal joints, toe in, camber/caster, sway bar position/bushings are things that come to mind. Tires that are old are difficult to balance and sometimes new balanced tires make the difference. Not all of these would apply to the Volt and there shouldn't be any wear issues but any time you make an assumption you can get led down the garden path.
 

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They kept it for almost a week and measured the vibrations while driving it, sent the results to Chevy, and told me Chevy said the measurements were within specs and to stop working on it, so they couldn't do anything else...
Really? The vibration measurements are "within specs"? Chevy has specifications for how much vibration is acceptable?

I would ask them exactly what measurements they took, how they took them, and what exactly the specifications are. Even of they measured exactly what you measured and have some maximal value that is not exceeded, that does not necessarily mean that you should accept this irritating wobble in a brand new car.
 

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I'm probably way off base with this, but I'd also take a straight edge and check the rear axle tube. If someone somewhere along the way decided (for some bizzare reason) to strap down the Volt by putting something over that tube it could be bent, seriously affecting your geometry and the vehicle stability.

Probably not the issue, but what popped into my mind.

PSA.... that rear axle tube should NEVER be used to tow or strap down the vehicle.
 

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Is the wobble more noticeable on certain roads? Certain types of surface? Does it vary with temp or does it vary in intensity after driving for a while?

Doesn't sound like tramlining, and I haven't heard of anyone complain of it on the Volt, but that also depends upon the roads you drive.
 

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Watch this from 2:45 on:


Faulty alignment would not normally cause a wobble. I'm betting a good wheel and tire shop can sort it out.
 

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yes- a double check at a local NTB tire store

or a loan of 4 tires for a quick test.
 

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Based on this thread so far, I have some observations:


  1. Don't go back to that dealership - their service department is useless. The Volt does NOT wobble. In fact, name them in the good/bad dealershp thread so other owners will know to avoid them.
  2. It's not tramlining. This requires tires that actually stick to the road and a grooved road. The OEM tires on the Volt simply don't provide enough traction to tramline and you're reporting this on all roads, some of which are bound to be not grooved.
  3. It's not Lane Keep Assist - you don't have this. That was a good thought though.
  4. It's not a "flat spot" in the tire as this feels more like a wheel balance issue but at low speeds.

Now what it could be:


  1. It could be a loose tie rod, but I don't think so since you stated the wobble smooths out as you approach highway speeds.
  2. Most likely, you have a tire with a broken belt. Does rotation from front to back change the feel? Also, have a good suspension shop perform a full alignment and check for damaged/loose/bent suspension components.

Chances are the solution will be to replace all four tires.
 

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Discussion Starter #13
Wow, so many replies! Thanks everyone. Let me see if I can answer the questions that came up.

They said the measurement was made with a "Pico", which I'm assuming is this: https://www.picoauto.com/products/noise-vibration-and-balancing/nvh-overview . They said a sensor clamps to the metal frame under the seat, and they drive the car around to measure the vibrations. I'm not sure what they specs are and what they measured in my car though, I didn't ask (I can if I go back and get further into it).

The wobble is the same on all roads, temperatures, etc., except there's an additional slight flat spotting after a cold night that lasts for a couple minutes when I first start driving, but that different.

The tire belt is an interesting idea... They did rotate the tires the first time I went, and it did feel a little different after, but it was subtle (if not just imagined, since I was anticipating a change). I have a couple questions about this though. First, would it be picked up during tire balancing/road force balancing? If so, they've done that a couple times now and detected nothing. The other thing is, how common would you assume this is? Since it seems a couple tires need to be rotationally aligned to feel the wobble, at least a couple of them would need to have this issue (I assume) in order for it to be the cause.
 

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First, would it be picked up during tire balancing/road force balancing? . . . The other thing is, how common would you assume this is? Since it seems a couple tires need to be rotationally aligned to feel the wobble, at least a couple of them would need to have this issue (I assume) in order for it to be the cause.
I would expect a good tire shop to pick up on a belt issue when balancing, but I wouldn't bet on a car dealer to necessarily look for that. As to the need for "a couple tires to be rotationally aligned," that is not the case. A single tire with a belt problem will cause a wobble. You said someone wanted to rule out a bent rim by checking the run out, so I'm assuming that has been done.
 

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Based on this thread so far, I have some observations:


  1. Don't go back to that dealership - their service department is useless. The Volt does NOT wobble. In fact, name them in the good/bad dealershp thread so other owners will know to avoid them.
  2. It's not tramlining. This requires tires that actually stick to the road and a grooved road. The OEM tires on the Volt simply don't provide enough traction to tramline and you're reporting this on all roads, some of which are bound to be not grooved.
  3. It's not Lane Keep Assist - you don't have this. That was a good thought though.
  4. It's not a "flat spot" in the tire as this feels more like a wheel balance issue but at low speeds.

Now what it could be:


  1. It could be a loose tie rod, but I don't think so since you stated the wobble smooths out as you approach highway speeds.
  2. Most likely, you have a tire with a broken belt. Does rotation from front to back change the feel? Also, have a good suspension shop perform a full alignment and check for damaged/loose/bent suspension components.

Chances are the solution will be to replace all four tires.

I'm voting for #2. The left-right experience is similar to what I've had driving over a bridge with a section of metal grate. You feel the treads switching between one groove in the metal grate and another making the vehicle shift left and right. A loose belt within the tread could be making the tread do a left right shift as it moves back and forth. The lack of it at low speed is probably due to lack of force. The lack of it at high speed is probably due to a stabilization of the wobble above a certain frequency.
 

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I'm voting for #2. The left-right experience is similar to what I've had driving over a bridge with a section of metal grate. You feel the treads switching between one groove in the metal grate and another making the vehicle shift left and right. A loose belt within the tread could be making the tread do a left right shift as it moves back and forth. The lack of it at low speed is probably due to lack of force. The lack of it at high speed is probably due to a stabilization of the wobble above a certain frequency.
I would also except OP reports the wobble occurs on all road surfaces. You don't get tramlining on a smooth surface.
 

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I would also except OP reports the wobble occurs on all road surfaces. You don't get tramlining on a smooth surface.
I suspect he was referring to the second set #2, being the belt issue. Belt shift/separation was my first thought, from the first post. I've seen this many times (dozens), and it's almost always a failed tire, new or damaged. Get it on a lift or jack, rotate the tire, and watch the tread. Any variation is a failed tire.
 

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I suspect he was referring to the second set #2, being the belt issue. Belt shift/separation was my first thought, from the first post. I've seen this many times (dozens), and it's almost always a failed tire, new or damaged. Get it on a lift or jack, rotate the tire, and watch the tread. Any variation is a failed tire.
That's actually my suspicion as well.
 

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Did this issue get resolved? I'm having a very similar experience with a 2017 Volt. The dealer balanced the tires. No change. The dealer replaced the driver side front axle and reported 70% improvement. Not good enough. The dealer is replacing the passenger side front axle now. How could the axles be the cause?
 
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