Originally Posted by Tripps2012
^^^What Gadget said also if you go with a 5K axle which will be overkill for sure the bolt pattern will match the truck with 6 on 5.5".
You can get 3500 lb axle in 6 lug, just need to look, but there is not much difference in a 3500 and a 5250, just swap out the springs if you get a kit or take a leaf out works fine, that is what I have done building trailers.
I think the problem is with the tube on a factory frame that when you cut it at the bed you need to plate some and then try to tie a tongue in to the factory frame.
The frame would be heavier then a new design, the factory design is built with the thought of towing, torque, and so on.
A tube or channel frame that tie to the bed mounts, uses trailer springs at a lot less weight, would make for a stronger setup.
The tongue could be an a frame front to back bumper and have a few cross members to tie the bed mounts, the bed will suport the weight like the truck does.
The other thing is a long spring like a truck spring will have more hop and bounce then a shorter spring, shocks help but the difference in the ride of towing loaded and unloaded will be so much that it will not be fun.
Some of you may know what I'm talking about....
Ever driven a truck with out a bed, the back end will hit a bump and there is not enough weigh so it starts the hop and it will come off the ground.
This is one reason trailer springs are shorter, to limit travel.
Travel in springs just is not safe for a trailer to tow.