Hello everyone. Big thanks to the OP for starting this thread!! Just read through all 14 pages. Sometimes this sort of perspective is what can help a thread along (or not), so here goes.
As others have pointed out, there are two issues here: 1) Flat-spotting; and 2) Vibration at speed.
I have a freshly-paved residential street (read: smoooth) in front of my house. I can notice definite shaking from the steering
wheel at 25-30 mph. Maybe this is flat-spotting, but as others have suggested there may be a correlation between the flat-spotting and vibration at speed. Ideally, I would want to drive my car out of the garage after an overnight rest and feel the shake. Then I should take my car out and drive the piss out of it (get the tires nice and warm), then come back home and park it in my driveway for a moment or two, get out and stretch my legs, and then proceed to pull out onto the road as if my car had been parked overnight. If this is true flat-spotting, then when I drive my car onto my street for the second time, the vibration should not be there at all at 25 mph. To my knowledge no one has done a controlled experiment like this. Many say the flat-spotting goes away after a few minutes driving, which it may, but to confirm this we need to control for as many variables as possible, like road composition, etc. I'll do it soon and report back.
As far as the vibration at speed. There have been a few (and only a few) who have reported back that changing to
aftermarket wheels or other Genesis wheels hasn't fixed the problem. We first need to confirm that the
aftermarket wheels are properly balanced. And if the replacement Genesis wheels don't fix the problem we need to confirm that the car from which they were borrowed doesn't have the same vibration problem because if it's the wheels then of course the new car they're put on will also vibrate.
Has anyone tried putting non-Genesis but still Hyundai wheels on a vibrating Genesis? From a car that you've verified via a test drive that does not vibrate? Like a Sonata, Elantra, Veloster, or even a Kia Optima for that matter. If we could verify that a smooth-as-glass vehicle's wheels and tires were put on a Genesis that we know has a vibration issue and the problem is solved, we'll know it's a tire and/or
wheel problem. If not, then we'll have strong evidence to point to a drivetrain issue. Which quite frankly is what Hyundai was probably aware of when they tried to solve the problem with a tire swap, which obviously didn't.
I hope that all makes sense.
FWIW, I have a 3-week old Genesis with the Michelin MXM4 tires and have both the alleged flat-spotting and vibration/shaking at speed. From about 40 mph and up it gets better or worse at varying speeds, but is always present at some degree.
Took it to the dealership, the techs said all the Genesis do this but to their credit they road-force balanced the wheels/tires anyway to try and appease me, without any noticeable improvement afterwards. They also let me test drive a brand new '15 3.8 AWD off the lot and it exhibited the same vibration at speed. The answer the dealership gave me to this "normal vibration" was to blame the Lotus partnership and the quest to get a more sporty feel, which to anyone that knows much about cars will tell you is total bunk.
At any rate, I wanted to put my .02 in and get subscribed since I have the same non-resolved issue.
Tony
Aboard and congrats on your new ride. Just some things to check into from reading may of these post. Check your air pressure as when these cars are shipped across the ocean they over inflat the tires and sometimes the dealers forget to lower to the required pressures. One poster on here experienced the same the type of vibration your experiencing and he found it to be a faulty AC pulley. Check to see if your vibration changes with/without the AC on. No matter what you do, take it back to your dealer and get it reported that you have an issue. Good luck and be sure to report back your findings.
