At highway speeds, my 2024 Kia EV9 becomes dangerously unsettled when the rear wheels encounter any irregularity in the road surface — expansion joints, potholes, manhole covers, raised seams, or uneven pavement. The rear end sways and hops laterally, feeling as though the vehicle is about to break traction and slide out of its lane. The effect is worst when crossing a bump at an angle or when only one side of the vehicle hits the irregularity, causing the chassis to porpoise and rock side to side.
The issue occurs on dry pavement at legal speeds with tires inflated to manufacturer specifications. It happens both in straight-line driving and through corners, and it significantly reduces my confidence in the vehicle's stability. In wet or slippery conditions it is impossible to tell whether the rear end is actually sliding or whether it is the suspension defect, which makes the car frightening to drive in poor weather. Passengers in the rear rows feel the motion most strongly, and every occurrence requires active steering correction to keep the vehicle tracking straight.
I have raised this concern with my Kia dealership, but they have been unable to diagnose or resolve the issue. Tire balancing, alignment checks, and inspections have not corrected the behavior. Based on owner forums and other NHTSA complaints, this appears to be a widespread defect affecting multiple EV9 trims, with no TSB or recall issued to date. Given the vehicle's weight and the potential for loss of control — particularly in inclement weather or emergency maneuvers — I believe this represents a serious safety defect that warrants investigation.
A D V E R T I S E M E N T S
At highway speeds, my 2024 Kia EV9 becomes dangerously unsettled when the rear wheels encounter any irregularity in the road surface — expansion joints, potholes, manhole covers, raised seams, or uneven pavement. The rear end sways and hops laterally, feeling as though the vehicle is about to break traction and slide out of its lane. The effect is worst when crossing a bump at an angle or when only one side of the vehicle hits the irregularity, causing the chassis to porpoise and rock side to side.
The issue occurs on dry pavement at legal speeds with tires inflated to manufacturer specifications. It happens both in straight-line driving and through corners, and it significantly reduces my confidence in the vehicle's stability. In wet or slippery conditions it is impossible to tell whether the rear end is actually sliding or whether it is the suspension defect, which makes the car frightening to drive in poor weather. Passengers in the rear rows feel the motion most strongly, and every occurrence requires active steering correction to keep the vehicle tracking straight.
I have raised this concern with my Kia dealership, but they have been unable to diagnose or resolve the issue. Tire balancing, alignment checks, and inspections have not corrected the behavior. Based on owner forums and other NHTSA complaints, this appears to be a widespread defect affecting multiple EV9 trims, with no TSB or recall issued to date. Given the vehicle's weight and the potential for loss of control — particularly in inclement weather or emergency maneuvers — I believe this represents a serious safety defect that warrants investigation.
- Noah W., Potterville, MI, US