The car shakes when going at speeds as low as 48 mph and as high as 68 mph that I know of. Typically, it shakes heaviest from the mid-50 mph range to the mid-60 mph range. I rarely Drive the full speed limit for energy conservation reasons, so I cannot tell you how much higher it goes on the range. The car has had the wheels rebalanced three times (installation, upon purchase from the dealer and on a take back to the dealership), the alignment has been checked twice and I have spoken to the tire manufacturer about the tires being the cause of this. I took the tires into an authorized retailer to no avail. With everything checked, including a road force balancing of the tires, my 4Runner still shakes disturbingly. I called a service advisor at another Toyota dealership today (they were not the seller). In describing the problem to him, he cut me off and said it is a known problem. He went on to share that the dealership had been in contact with Toyota Corporate. It is disturbing for me as a driver, my passengers and from an engineering standpoint; shaking can never be good. It could easily cause premature and unnecessary wear to drive, suspension and steering parts. It could lead to a serious and fatal accident over time. The shaking, I imagine, could also lead to a problem in less than ideal driving conditions such as rain, snow or ice as well.

- Carlsbad , CA, USA