This information may not apply directly to your build but I like to post it for general information...
Error on the side of caution and have a failsafe design. Loosing the tire carrier on the fwy could easily result in GBI or death for someone behind you.
Rear tire carrier design FAQ
Originally posted by Tankota (TTORA)
"That's the same exact type used on my old one. They are using mini axle spindles, kind of like you would use on a small trailer. They are plenty strong as is, but the weak point is where it's mounted to the bumper. The stub is usually hardened, and when they weld it to the bumper it weakens them at the base. Then the light rocking back and forth of the tire on the gate over time causes fine fatigue cracks at the base, and eventually it goes all the way through the spindle. It all depends on how well they are controlling the bouncing of the gate, and how good their welding is. If you are driving down the road and you can see the tire moving front to back at all, then it's flexing at the base, and over time will cause the metal there to weaken and fail. Kind of like bending a paper clip back and forth. The more the movement, the faster it will break.
Some of the Jeep bumpers have a latch higher up, and this works well to control the movement. If you look at some designs, all the weight is hanging off the gate at an offset (tire), and the mounting points are all below the gate at the base, with nothing to stop movement at the top.
This is the reason when I built my new rear bumper I used 2 hinges, and 2 latches. It's not as low profile and clean as those types, but it stops the movement, even while off-road. Plus it's almost impossible to have both both hinges and both latches fail at the same time. Mine's way overbuilt, I sat there making sure almost everything had at least 2 attachment points. That way if I start to have any problems I can catch it before hand.
Now there are plenty of bumper built that way that never have this problem. I'm sure that's a very nice high quality bumper, and I have no knowledge of any from that company having problems. But I have heard of at least 6-7 built with that type of hinge that have failed, in addition to mine, and that's just from 1-2 message boards so who knows how many have had problems that never made it onto those 1-2 message boards. This problem is very hard to detect ahead of time, you have to remove the entire gate and bearings and examine the base of the spindle where it's welded to the bumper and look for hairline cracks. This type of failure could take months, years, or never. Mine was about 2-3 years old when it failed."
