Hi Oscuro, thanks for the compliment. Used wheelchair parts are great for building things with. I had thought about building a level bed trailer using independent quick release axle assemblies, but decided I didn't need the loading area. I considered the parts shown below that happen to be from Sunrise Medical catalogs, and the axle parts as pairs are usually rated in the 250 pound range. I used a previous version of the ultra lite spoke wheel assembly on my trailer. It was available as used, weighs very little, and runs 24x1" Primo clincher tires @ 110psi. Wheelchair wheels are almost always radially spoked for lateral stiffness. Maybe your local wheelchair shop could source you some cheap or even free used parts?