The back end of the car will move back and forth laterally when driving over uneven road. In particular it appears to happen when driving over a bump while also driving at a slight left or right angle. After the bump the back end will oscillate laterally. This is extremely concerning to the driver and passengers, it can feel like the car is going to bounce out of its lane.

- Ashburn, VA, USA

I am experiencing significant and persistent vibrations at highway speeds (60-?"75 mph) in my 2024 Kia EV9. Despite multiple dealership visits and repair attempts, the issue remains unresolved. The vibrations cause noticeable discomfort and potential safety risks, especially on long drives. Timeline of Events & Repairs: 1.First Visit to Kia dealer (Dec 24): The dealership performed a tire balance and determined one tire was defective, replacing it. Vibrations persisted. 2.Second Visit (Jan 25) The dealership replaced the remaining 3 tires 3. ThirdVisit (Feb 25): The dealership identified three wheels with lateral runout and replaced them. They also performed road force balancing, reportedly bringing all values below 16. 4.Test Drive (Feb 25): After picking up my vehicle, I drove on the interstate and found the vibrations had worsened, now starting at 60 mph instead of 70 mph. -??A third-party wheel shop inspected the wheels and found the fourth wheel (not replaced by Kia) was defective and out of round. 5.Dealership-??s Response: Despite these findings, Kia dealer dismissed my concerns and referred me to another dealership for a second opinion. They also stated that third-party evaluations are not accepted, creating an endless loop where I cannot get the issue properly addressed. Safety Concerns: -??Vibrations impact vehicle stability and driver comfort, especially on long trips. -??Extended driving with excessive vibrations may lead to fatigue, reduced control, and premature mechanical wear. -??The fact that multiple components (wheels, tires) have required replacement raises concerns about a potential manufacturing defect affecting Kia EV9 models. Request for Investigation: The dealership has failed to resolve this issue despite multiple repair attempts, and their refusal to acknowledge third-party findings leaves me with no clear resolution path. I request that NHTSA investigate potential defects in the wheels, tires, or drivetrain system of the Kia EV9.

- Bradenton, FL, USA

When you're at speeds greater than 15mph and hit a bump or encounter a surface irregularity (pothole, expansion joint, etc.), the Kia EV9 GT Line goes into a porpoising sway, causing the entire chassis to become unsettled. The swaying is much more pronounced when only one side of the encounters the irregularity, or if the car is not perfectly perpendicular to the irregularity and the left and right wheels pass over the irregularity at different times. The effect is especially noticeable in the rear. This unsettling 'swaying' increases with speed and happens both while driving straight and through corners. The rear end feels as though it's hopping or skipping from side to side. Out of all the vehicles I-??ve driven-?"and I-??ve driven quite a few-?"I-??ve never experienced anything like this. During wet and slippery conditions, driving over small bumps or manhole covers has even caused the vehicle to lose traction and begin spinning - even while traveling at 25mph in a straight line. I purchased the EV9 in early 2024 and it has had the issue since delivery. I have heard many other EV9 GT Line owners complain of similar suspension issues and I am frankly surprised that there has not been a string of crashes and fatalities linked to the issue. I have spoken to the Kia dealership several times but because the vehicle is new they claim that they have not heard any other reports and they do not have the experience to diagnose or fix the issue.

- Marysville, WA, USA

Vehicle suspension experiences rear end swaying at speed when encountering rough or uneven road surfaces. Vehicle is available upon request. Rear 2 rows experience it more than front but requires driver to be mindful of steering to maintain control of vehicle. Dealer replicated swaying on vehicle and new 1 off the lot on 11/11/2024 per service invoice. Dealer service department test drove, rebalanced all tires, performed alignment, 8k service, and has performed 4 multi-point inspections since purchase in July 2025. No warning indicators, codes, or lights on dash and as stated on service invoice.

- Fredericksburg, VA, USA

When driving over uneven surfaces, like typical urban and suburban roads and highways, the rear end seems so wobble and slide. It feels like the heavy EV is about to break traction and slide sideways. It porpoises as well. It makes every passengers heart skip a beat. These are on dry roads, obeying speed limits, with the stock tires. An expansion joint, seam of two types of road material, utility cover or other irregularities can cause this. Easily reproduced but dealers or Kia America don-??t seem to believe or care.

- Sunnyvale, CA, USA

The Kia EV9 has a defect in its suspension that causes the rear end to "bump-steer" over imperfections in the road, giving the driver a scary sensation of losing control. For example, driving on the highway in a corner, if you hit an expansion joint or pothole, the vehicle will require a quick steering correction while the vehicle's rear-end enters what feels like an oversteer condition. This reduces confidence in the vehicle's ability to hold the road. In poor weather like snow, it's impossible to discern whether the vehicle's rear end is sliding, or if it's the bump-steer condition occurring. My wife refuses to drive the car in inclement weather, despite the vehicle being fitted with snow tires. It is a very scary feeling. Kia has yet to issue a TSB for this on 2024 and 2025 model year vehicles, and it seems that all trim levels are affected after discussing with the community on forums. Even after dialing in the alignment perfectly to manufacturer specifications, the issue does not resolve.

- Endwell, NY, USA

We've had the vehicle for about six months as my wife's primary car. within the first week of driving the vehicle, she noticed it "hops around" when encountering irregularities in the road surface at highway speeds. After driving it myself, I agree-?"the vehicle gets unsettled while driving over seams, bumps, or uneven surfaces, even minor ones like raised seams or potholes. This happens and is most noticebale at highway speeds, both while driving straight and through corners, with the rear end feeling like it's skipping, hopping, or "porpoising." Even with small irregulairities in the road the vehicle lightly sways. Tire pressure is set to manufacturer specifications, and there's no noticeable irregular or excessive wear on the tires. When I have spoken to the dealership about this, they cliam that it's perfectly normal becuase it's a heavy vehicle (referencing a 3/4 ton pickup). This does not inspire confidence in dirving the vehicle and is likely to cause an accident.

- Cincinnati, OH, USA

At highway speeds, the SUV experiences significant body sway when hitting a bump, causing it to rock side to side in an unsettling manner. This issue makes the vehicle feel unstable and nervous, requiring the driver to slow down to regain control. The excessive body roll presents a potential safety hazard, as it could lead to a loss of control in certain conditions. Based on my research, this problem appears to affect the GT-Line model more than others. A solution is urgently needed to address this serious handling issue, but so far, Kia Corporation has done nothing to resolve it.

- Hawthorne, NJ, USA

The manufacturer failed to align the vehicle at all prior to leaving the factory. The failed parts all have to do with the alignment. My safety was put at risk because of the persistent pull while driving, shaking while driving, instability at high speeds, and the fact that the tires are now damaged due to the alignment issues. The dealer kept the vehicle for over 60 days, and was able to rectify part of the alignment issues, but there are still areas that they are unable or unwilling to fix, as shown to them by the alignment machine. The vehicle has been inspect by a certified Kia dealership, as it was there for over 60 days. The issues were the shaking of the vehicle, the pull, the instability at high speeds, and the damage caused to the tires. It appear upon first taking the car home after purchase. I was forced to pick up my vehicle because Kia was unwilling to fix the vehicle, and they threatened me with storage fees.

- San Antonio, TX, USA

The whole car vibrates at highway speeds. You can feel it in the steering wheel and the center armrest console. Dealer has balanced wheels twice and performed alignment but nothing will fix it.

- Diamondhead, MS, USA