Problem: unstable & inadequate jack for vehicle. i had a flat on my vehicle and used the factory jack. while pulling the tire off the lugs the vehicle shifted and the jack fell over. luckily the tire was still within the wheel-well and tire/rim broke the fall. even though i was on a flat level concrete parking lot, the stability of the jack is poor (very small footprint and top of the ram is also small). not very much front-back movement causes instability for the jack. in addition, the maximum jack height provided barely enough clearance to put a new tire on (20? factory tires). this would have not been possible on any other surface like the shoulder of a highway. i do admit that i had not properly ?chocked? the tires that allowed for more movement than normal, but the movement that caused the fall was not excessive. i personally rotate my tires on all four of my vehicles frequently using a floor jack and never have had this problem. the factory jack is unsafe and undersized for this large vehicle (suburban). a co-worker also experienced this same accident with his tahoe while in his garage. *tr