I decided to switch back to the 21s tonite. Sometime after swapping the driver's side front and moving to the driver's side back, the Jack mode decided to disengage without saying so in the car. The rear wheel just wouldn't loosen up (despite all bolts being removed) so I jacked it up a bit more and heard a pop. Scared the flip out of me. At this point I lowered my floor jack, gingerly opened up the driver's door, sat as lightly as I could, tapped on the brake, and then pressed Jack mode to re-engage it. From there everything was normal. Anybody else had this happen? My new protocol: Toggle Jack mode on and off between each wheel to be sure there's no timeout that kicks in. Sidenote: Some might be thinking "how long does it take you to change a wheel?" The top of the lug nuts is very squishy. Unless you land the socket just right they bend easily and make it extremely difficult from there on out. I'm lucky enough to have a second set of lug nuts, because today I swapped in 3 of them due to this problem. Going to have a chat with the service center about bubbling this up to corporate because it's a real issue, IMO.