this is a scale trailer I made for my nqd jet boat. I used pla+. it has working leafsprings. I glued and bolted all pieces together and have not had anything break. Use m3 hardware. two different 12mm extensions mattering on the rim you choose. I chose a small 1.9 this way didn rub. you will also need wo 6700zz ball bearings and a length of 5mm ready rod. slide rod through extensions axles and wheels and cut to length.