They are all season, size 215/55R16. I don't believe they are directional.
I read somewhere that if they were the tires the sound wouldn't go away at 70, it would get louder. Is that true?
Neither place will try putting other tires on or entertain the idea that they are the tires as they have tested them on machines or something that tests the roundness and density and I guess as well as looking at them.
The car was aligned when the tires were put on and has since been rechecked to make sure it was correct.
I'm assuming the lower control arm bushings are fine because after the struts were replaced the clunking noise stopped when hitting bumps.
In reading about the noise the exhaust flex pipe would make, that sounds like it would depend on the engine and this hum is only specific to the wheel speed.
I couldn't really find many people complaining about this particular tire being noisy.

 

Neither place will try putting other tires on or entertain the idea that they are the tires as they have tested them on machines or something that tests the roundness and density and I guess as well as looking at them.


You said earlier that you have a Warranty that has about 2 weeks left that says they will replace for any reason ??
In this case .. You cannot test tires on a machine for the same conditions/issue as on your car driving..
Remind them again that there was no noise until they installed these tires .... Period.
Until you put that issue to rest you will continue to be guessing.
Maybe you should also remind them that they have led you down the path with all there so called fixes.
I think they may be worried that if they find it is the tires, they will have to compensate you for all there mistakes.

Silverfox

 

Yes, what Silverfox posted! And don’t think that a noise can be from one thing at the age of the car you’d be surprised at what can rattle, clunk, grind and whine.
I believe it’s bum tires, have them replaced by a different brand.

 

it's not a matter of faith or trust ...
It's easy to check just by looking at your tire.
I was not too lazy to find a picture and look at the tread - it's asymmetric. Asymmetrical pattern = directional pattern.
You may find it helpful to make sure your tires are guided correctly. The sidewalls of directional tires are always marked with correct fit.

 

Look very closely at the tire sidewalls, inner and outer. Look for bubbles, bumps, pinches especially around the rim.

Forget anybody citing rules for speed vs road noise. Maybe typically, a poorly balanced tire will vibrate more 55mph to 65mph then settle out; but that ain't a rule.

re: flex joint: tire speed is related to motor speed. Hood up, idling can you hear it? Have your lovely assistant rev the motor; can you hear it?

Has anyone actually looked under the car for loose plastic parts, paper bags, flotsam, jetsam etc?

Are both rear seat windows fully closed?

Knocking going over bumps has to do with the sway bars not the LCAs. You have to test them by trying to roll the tires, if the tire moves before the body does they are bad. Alignment guys don't check them very often.

 

So, it was the tires. We replaced them with Hankook Kinergy ST and the noise went away. Now though there is a thump thump thump noise. The tire place was a disaster! I don't know if they purposly didn't balance the tires or did it wrong and the weight fell off, but we immediately had to take it somewhere to have the tires balanced and they said they had never seen tires so out of balance. Unfortunately though, there is still a slight thump thump thump at around 30 mph as well as a slight vibration corresponding to the thump. It's most noticeable on a super smooth road. I'm wondering if we have a bent rim due to it being so out of balance and driving it 25 miles to have them balanced? I'm so disappointed as I love this car and it is just not fun to drive in its current state, but we have thrown so much money at it and we just don't have more to give at this time. The vibration isn't terrible (like when it was out of balance) so I guess I'll live with it for a while anyway. Thank you to everyone for all the suggestions!

 

You could try putting the spare tire on, see if the thump goes away. Move it to different positions if necessary.

 

Wheels don't get bent from being out of balance. Only from hitting things.