If your building a trailer, I've got a little tip for you. One of the things I've added to all our trailers is a second axel, even if it doesn't need it for the weight. Having that second axel adds a lot of safety if a tire blows on a loaded trailer. I've had tire blow-outs on four-place snowmobile trailers with only one axel and it was scary and dangerous. The second axel helps out a lot. I even prefer it to a single axel/dually setup, as it gets better traction in bad weather.