2017 CX-9 Signature, Vibration on Highway when 65 mph+

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Mazda CX-9 Grand Touring 2016
eplur, great job of standing up for yourself. If there is a problem with one or more tires or wheels (unlikely to be all four) then a competent tech on a road force balancing machine can find it. Two requirements there...first, the machine that detects road force variations, and second, the tech that knows how to run it properly.

Here is a very informative article about tire vibration causes: http://www.tirereview.com/when-is-it-overkill/

Here's the machine that's needed: https://www.hunter.com/wheel-balancers/road-force-elite
This is the newest machine that does the job more quickly and does more for the tech. Older version do a fine job, but require more knowledge from the operator.

In all these cases, we need to stop talking about balance. Rebalancing a tire with a different problem yields the same vibration. Just talk about vibration. Their can be several causes of vibration other than balance.

Don't forget your big gun--the Lemon Law. Here's New Jersey's version: " The defect must substantially impair the use, value or safety of the vehicle or be a serious safety defect which is likely to cause death or serious bodily injury if the vehicle is driven." eplur's experience seems to qualify here. I'm not suggesting that he file to have his car bought back, 'cuz now it's fixed, but just the threat of a Lemon Law claim should get the dealership and the manufacturer regional rep off their butts. Each state has their own version of a Lemon Law, so if needed, check your state's version. (My state has a wrinkle--it only applies to cars bought in-state. That maybe be a consideration.)
 
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2018 GT
I went silent for a while cause I was giving up on getting this fixed after my last visit to a dealer. Mazda corporate lined up an appointment and upon looking at the car the Mazda Tech from the phone was determined it was related to the hitch I installed and towed a jet ski. They wanted to pull appart the rear diff and look for water intrusion lol. I hadn't even backed the car up to the lake yet for the one time I towed my ski. I wasn't willing to start ripping apart the car looking for a whild goose chase on this issue. It is very hard if not impossible to feel through the wheel, if you put the visor down it shakes, the passenger seat shakes when empty and the drive side rearview mirror and the regular rearview mirror all vibrate above 65mph. This happens with the 20 inch OEM or 18's I am currently running so really dont' think it is a tire issue. None of the dealers I went to wanted to spend any time trying to figure it out and most were not very nice when speaking with me. I gave up, was hoping someone would find a fix. In the meantime I am living with it as I like the car other than that one issue.

After driving two others they both seemed somewhat the same so I wrote this off as the car itself. What I am not sure of is if alignment could cause this feeling by itself, that has not been checked yet. Would love to have it be smooth.
 
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2018 CX-9 SIGNATURE
After driving two others they both seemed somewhat the same so I wrote this off as the car itself.

I'd like to hear more about that.

The first couple months I owned mine I rarely had this issue but I did. It was intermittant to the point I thought I might be imagining it thinking it was the road surface.

Again, when it did happen, it was rare.

There was one instance where the passenger side gap in the rear seats was rubbing from vibration and making so much noise, I pulled over and physically separated the seats the best I could which stopped the racket.

After the first Mazda service, including tire rotation, I don't think the vibration has ever come back.
 
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2019 CX-9 GT Machine Grey
Just another update. Have driven another 1500 miles since the last rebalance( 3rd time) that the dealer did. The vibration is now very minor. Finally got to drive on highway for 150 miles straight at all different speeds. I sometimes feel it slightly at various speeds 50-80 mph in the seat. No vibration in steering wheel, the mirrrors dont vibrate although visor does slightly at times. This last roadforce the dealer got the numbers slightly lower on 3 tires with one having 15lbs, two at 13lbs and one at 7lbs. So in addition to people getting roadforce I would concentrate on getting numbers below 15. 15lbs is the spec GM uses so it must carry some weight. Some say anything under 20lbs is acceptable on an SUV. The CX-9 is more like a high riding car than a tradional SUV like a Tahoe. I do think the combination of low profile 20 tires, stiff suspension and stiff chassis do make it more sensitive to any vibration. Anyway Im not pursuing it further unless it gets worse. I also test drove a 18 CX-9(100 miles on car)with Bridgestones 4 months prior to my purchase. It had a horrible vibration. Rear view mirror a blur. So Im happy for now. Other than a glitchy/slow to boot up infotainment system Love the car. Its better than my Wifes 17 Lexus RX 350 on many levels.
 
I just bought a 2019 cx9 signature have the same issue, had the car for a week now. And I also have brake issues too, it grinds and making noises everytime I am slowing down. Will drop off the car tomorrow morning. Hopelly they can fix everything.
 
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2018 GT
I gave up on chasing the issue. Wheels seem fine. Just now accepting that the driver mirror and rear view will vibrate at times while going above 65mph. I also think it is something to do with the road surface, cause I notice it more close to home than on longer trips. Not bad enough to worry about it anymore and my 20's vs the 18's don't seem to change it, so not going to keep chasing something minor.
 
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Update for my 2019 cx9 signature. Dealer rebalanced my front passenger tire and replaced all four rotors, they found some hot spots on those rotors. So I got the car back last night and I went out, put about 50 miles on the car, it drove nice and smooth, but this morning when I drove the car again at speed 50mph I felt that vibrantion again under my seat. And the car is equipped with some bridgestone tires from the factory. I think the problem are from those tires. But the car only have 600 miles on it. I really don't wanna spend another $1000 for tires. I will drive more to see if it's really the tires.

Please help us if anyone knows what causes the vibrantion when cursing 50-75mph but the car is quite. Please help.
 

sm1ke

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Canada
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'18 CX-9 Signature
Update for my 2019 cx9 signature. Dealer rebalanced my front passenger tire and replaced all four rotors, they found some hot spots on those rotors. So I got the car back last night and I went out, put about 50 miles on the car, it drove nice and smooth, but this morning when I drove the car again at speed 50mph I felt that vibrantion again under my seat. And the car is equipped with some bridgestone tires from the factory. I think the problem are from those tires. But the car only have 600 miles on it. I really don't wanna spend another $1000 for tires. I will drive more to see if it's really the tires.

Please help us if anyone knows what causes the vibrantion when cursing 50-75mph but the car is quite. Please help.

I've read that for some people, the OEM tires were flatspotting overnight, which would explain why the car drove smoothly when you got the car back, but vibrates the morning after.
 
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2017 CX-9 GT AWD
I've read that for some people, the OEM tires were flatspotting overnight, which would explain why the car drove smoothly when you got the car back, but vibrates the morning after.
Ditto. Every night my tires flatspot, sometimes even after sitting for 3-4 hours during the day. The slight vibration from the flatspotting goes away in about 5 miles.
 
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