The amount of weight, both static and dynamic, that the barn door hinges can take has been my recent concern. I'm always suffering OCD regarding any door of a car swinging fast open and cause stress on the door checks. This all started one day when I saw an F150 driver opens his door and just let it fly out.....cringe. Anyway, so my GX460 barn door swang open by itself today before I could grab it, sure this was nothing, but it made me wonder how much vertical, horizontal, static, and dynamic stress the hinges can take? This surely is relevant for adding spare tire to the GX, you won't always be mindful to hold on to the door, it can fly open, it can bounce when driving on washboard roads etc etc.I share a lot of concerns as other with door mounted option. The main difference in Prado and GX doors is the sheet metal is formed on the Prado with reinforcements to address the extra weight on the end when closed and open. If you have seen the Expedition One bumper that mounts on their bumper but is hinged to the door they have had issues with the sheet metal pinching. The JW mounted one I haven't seen a failure, but I'm also not convinced the majority of people are driving aggressively enough with it. I know JW has great customer service, but replacing the rear door is probably not something they are going to warrant and claim install error etc. Currently, for a rear door mount the best solution is a Prado swap or the Expedition One bumper with the updated hinge system to fix the pinching issue I described earlier; both attain a similar experience where you open the door and the tire swings with the door.