I stumbled upon your posts here. You have an excellent product, I hate to see you stop making it and selling. I think your product has more than enough strength to do the job that is asked of it.
As a comparison, Ford, GM and others used a simple stamped metal bracket that attached to the body with far smaller hardware to hold the tires in the cargo areas of Broncos, BroncoII, Blazers, Jimmys, Vans, etc... They also used a simple large wingnut and half inch floating cariage bolt to hold the tire to the bracket.
We had an 86 Bronco growing up, half the time, the washboarded dirt roads would rattle the big wingnut loose and the tire would be rattleing then. We had to make a big rubber washer and stuff a blanket behind it to keep it tight and free from working loose. The entire bracket and tire still would shake and shimmy on rough roads. THIS WAS A FACTORY PART people, far less substantial than the mount Mtbcoach is building that I can see.
Yes we had a stock sized tire in the back of that Bronco, yes mudders have bigger tires often times. If you are worrid drill out the hole for a bigger bolt, but a half inch bolt has an immense shear strength. Your body, heavier than a tire, is only held in the car by three bolts and a nylon strap. The seats attached similar. These items typically don't break the bolts off and go flying around the cab, and when they do, things have gone really bad.
Give this guy a break, we are a community, if you want to buy something from a guy he built in his garage than understand it didn't under go millions of dollars of safety testing a Toyota and use it at your own risk.
Examples of interior carriers, top BroncoII, below full size Bronco.
