Here's my story:
Purchased a brand new 2015 Genesis 3.8 AWD Signature and noticed vibration on steering
wheel, seat and on my feet (at 40 mph+ and 60 mph+). Dealer stated that all Michelin MXM4 tires have some flat spot. They did road force balance and showed me the results. Two fronts were 17 and 18 lbs. and two rears were 23 and 24 lbs. According to them, two fronts were within the spec (15~18 lbs.) and so they replaced rear two tires yesterday. This sounds easy and fairly quick but took me whole month w/ dealer playing game. (3 total visits, contact sales, service manager, the owner of dealer and they processed thru HMA, etc.)
Anyways, when I drove out from the dealer, I noticed rough vibration in seat and on my feet, but went away after couple of miles driving. This morning driving to work was same thing. Noticeable at first few min. and fine (within 50 mph speed). However, I can still feel (less than before but noticeable) vibration on steering
wheel, seat and on my feet when driving over 60 mph. So, although vibration got much better, it's still there. And my guess is that initial flat spotting is normal (?) in this tire? Temperature is about 50 degrees here in Chicago and the car was parked a few hours at the dealer and overnight at home before I drove each day. They have set the tire pressure at 31 psi and goes up to 33 psi when driving. I don't know if this is true but they told me that vibration from body of the car (which I feel on seat and on my feet) is coming from rear tires and vibration from steering
wheel is from front tires. Also told me that I can feel more vibration if the tire pressure is set at higher psi.
Well, how bad is this vibration? It all depends on each individual but I'm pretty sensitive when it comes to driving and I can definitely feel it all the time although my wife is saying she can somewhat feel it if she pays attention about the issue but for the most of time, it doesn't bother her specially driving with all other road conditions/noise...
With mixed up feeling I'm having at this point, I think I'm done w/ dealer for this issue. Maybe I can go to 3rd party shop (discount tires or tire rack) and re-do the job at my expense? (hopefully they can warranty two fronts or maybe if I can swap them all with different brand?) I'm at less than 2,000 mileages. Any suggestion?
Other than that, I love the car. I wish I can fix this issue soon so I can move to the next project: tint the windows and install fog lights.