I have run them for 20k miles. No wheels pop off yet. I did say yet. I am running the same size tire. You are gonna most likely have to crank the T bar some to get them in there.

 

just keep an eye on your sidewalls. Mine wore in an 1/8th inch before I realized that they rubbed. That, and they rubbed the side of the control arms and the sway bar at full lock before the spacers.

 

Back in the day, spacers were considered a no-no and everybody had a horror story about someone they knew with a horrific failure.
But anymore, a LOT of people use them and I've only heard about a couple problems, usually with broken studs...