Seats and floor shake at low and highway speeds

[checkstr]

Wondering if anyone has or is experiencing vehicle shake when driving at both low and highway speeds?  A little more info:

 

1) Shake starts around 65 km/h (40 mph) It levels out for a little but then comes back again around 100-110 km/hr (60-68 mph) and intensity of the shake continues above that speed

2) Felt primarily in the seat and floor.  When i look in the rear-view, I can see the back seats shaking.

3) 2014 DJ Ltd.  Bought used

4) Does this with the 19" OEM alloys and also with my winter tires which are brand new as well as the steel wheels they came on. 

 

I know that usually vibration felt in the steering wheel is front end issues, and seat and floor vibration is typically rear issues.  I am not so certain it is balance or tire related as it happens with two different sets of tires and rims.  If it is not that, what else could be causing this?

[OhareFred]

Rotors could be warped.  My first guess was  tire balance.  I also have the 19’s and always have to return for a second balance because they screw up the first time and I get a vibration.

[2late4u]

i would have the alignment checked and while on the rack see if the frame has been damaged from a wreck, and not fixed properly.also could be bad struts/shocks on the rear, was driving down the road last week and a older car passed us and both of his rear wheels were bouncing up and down really bad. bad tires with broken belts could be a cause, also bent rims but since you have 2 different sets kind of rules that out. if all else fails get it into a suspension shop they should be able to figure it out.... front wheel drive or all wheel drive?if awd could have drive shaft  problems. good luck

[checkstr]

The car is FWD.

 

Alignment was done as I had to replace the front ball joints.  There was no change either before or after the alignment was done.  I'd be pretty angered if the frame was bent, although I wasn't aware that this type of shaking could be an indication of that...I always thought bent frames show themselves more with alignment issues and uneven tire wear. 

 

Just to be on the safe side before I explore the possibility of a bent frame, I'm going to have my tires road force balanced to see if that improves anything. 

[2late4u]

well good luck anyways, since both sets of tires are causing the same conditions i would think that inst your problem but if the same garage did the balance maybe?i remember someone on here was having problems with their tires being balanced  i think it was at cosco and they were using the wrong adapter that thee tire was setting on while being balanced.keep us informed on what you find

[checkstr]

So...Still no luck with this vibration and it is driving me crazy!!!  Here is what I have done since then (as I am really trying to rule out the tires/rims before I explore further:

 

1) Had those tires taken off the rim and then re-set and road force balanced.  No change.  They re-road force balanced and still no change.  The shop is at a loss (and so am I).  It is a tire specialty shop that I am using and have used them with great results in the past (although not with my DJ).  They are at a loss and quite frankly, so am I.  Aside from possible frame damage which has yet to be explored, they mentioned that it could possibly be a broken motor mount.  He is no mechanic but is going off of his personal experience.  My engine does move around quite a bit when starting, and I do get the odd jolts when the transmission is shifting gears (mostly between 2nd and 3rd).

2) As a last ditch attempt, the shop swapped out the General Arctic 12's that I had on it (they were brand new winters), and replaced them with Continental Contact Si Winter tires (brand new as well).  Exact same issues I'm having.

 

A couple extra observations:

 

1) The vibration felt is mostly in the floor/seats, and although felt while accelerating over 60, you really start to notice it over 65.  And if I take my foot off the gas and coast (no brakes applied), it is really bad...Almost feels like the car is going to fall apart.  When I accelerate again, the vibration persists, but it's definitely not as bad.

2) My car is FWD, and is the V6.

 

Is the rear suspension on the FWD a shock and strut assembly?  If it there is a strut, I think the rear passenger side might be on the way out.  I keep hearing knocking sounds when going over bumps (kind of like something is inside my car making that sound), but there is nothing there that I could see.

Also, what other components in the drivetrain are rotary?  ie : U-Joints, CV Joints...I will be taking it in next week to have my suspension looked over, but would also like to point out a few things that I'd want them to look at too as well.

 

Thanks!

Edited November 16, 2018 by checkstr

[Jalynsdad]

We have had this issue with our vehicle a few times, including currently. Does your vehicle happen to have Kumho tires? Our 2015 came with the 19's with Kumho tires from the factory. At about 25,000 miles we started getting a shake in the vehicle similar to the one that you described. Turned out to be one of the tires developed a huge knot and was trying to come apart. Dealership replaced the tire for free. No big deal. A few months later the shake is back. This time I inspect the tires myself and find that 2 of them have knots (one of which was the one that was already replaced). Dealership replaced the tires for free. About 6 months later, yet again two of the tires knot and start to come apart. At this point, I ask the dealership to replace the tires with a different brand, which they refused. Said that they would replace them with the same tires that the vehicle originally came with. I ended up just going to the tire shop and buying 4 new tires for the car. I believe that I bought Michelin tires. Have had these tires on the car for over two years now and have had no problems at all after driving about 45,000 miles. Tire shop said that it must have been a manufacturing issue with the specific size Kumho tires that hadn't been corrected yet. 

[2late4u]

my 2014 has 19 rims so, not long after buying it new i rotated my tires myself and felt a vibrations took it in to the dealership  they balanced all the tires checked the rims no problem they said well after driving it home i still felt it, so i rotated the tires again the vibrations went away so i was still at home so i moved the right tire to the rear took it for a drive no vibrations so then i rotated the left to the rear and then felt the vibration back so i drove it to the shop showed the manger which tire and told him what i had done so they check that tire and rim and said no problem i said bullshit replace the tire and or the rim, so they went for a ride and felt the vibration then we went back and they moved it to the front and took an other ride no vibration, well they replaced the rim and tire, so i dont know what was bad the tire or the rim but i was taken care of. that was the only problem i have had with my Kumho tires my 2011 17 tires i got around 50k and still had some tread left but my 2014 with 19 tires i only got around 30 k with some tread left.. had some coopers put on liked them and i know have you guessed it Kumho back on (Great deal on them saved me some $$) got about 10 k on these and looking good and riding good.

Edited January 9, 2019 by 2late4u