[jeffspower]

That's a whole lotta truck for a typical 18 ft. bumper hitch trailer. I don't think you would need to worry about the duals clearing the trailer fenders- the front wheels will be off the front edge of the trailer before the duals hit the fenders.

The trailer would need to have a 2-5/16" ball and trailer tires (not car tires) if they are just 15 inchers on 3,500 lb axles before I would do it. And then I'd be thinking about my route/ surfaces/ hills etc. It could get out of control very easy. Been there done that and got lucky once.

Better to find a bigger trailer.