I have a 20 foot flatbed that's been built from scratch, with the original idea of doing the "redneck toy hauler" plan - small camper on front of trailer, 4x4 on back. I quickly figured out that my original construction didn't quite meet my dreams, largely due to overloading of the tow vehicle with far too much tongue weight with just the 4x4 loaded. Basically, just to keep the suspension on my truck from bottoming out, I had to keep the 4x4 on the trailer back almost as far I could get it, and this was without a camper loaded on the trailer. It did tow quite nice though 
So I figured I needed to move the axles forward to help balance things out a bit, as the current configuration would only make the situation worse once the weight of the camper was added. I went from roughly a 70/30 split to a 55/45 split. Rather than continue the trial and error method (not to mention, potentially buying a camper that's too big and/or too heavy), I'm thinking I should do a little bit of math here to see what my final loadings will be in various loading configurations.
I remember seeing at one time a web app where I could plug in the trailer length and axle location, and be able to play with various weights placed at different points on the trailer with a print out of what axle loading and pin loading would be, but I can't find it now. The only thing I'm coming up with calculators for determining what loadings will be with weight evenly distributed over the trailer, which isn't exactly what I'm doing here.
So I figured I needed to move the axles forward to help balance things out a bit, as the current configuration would only make the situation worse once the weight of the camper was added. I went from roughly a 70/30 split to a 55/45 split. Rather than continue the trial and error method (not to mention, potentially buying a camper that's too big and/or too heavy), I'm thinking I should do a little bit of math here to see what my final loadings will be in various loading configurations.
I remember seeing at one time a web app where I could plug in the trailer length and axle location, and be able to play with various weights placed at different points on the trailer with a print out of what axle loading and pin loading would be, but I can't find it now. The only thing I'm coming up with calculators for determining what loadings will be with weight evenly distributed over the trailer, which isn't exactly what I'm doing here.
