The tail wheel supplied with the kit is a sturdy nylon two part assembly. However, as I changed the design to having a separate servo for the tail wheel, I needed an arm to secure the housing. This gave rise to a new design which I proceeded to make out of aluminum. The original design used a spring encapsulated in brass tube with a piston as a shock absorber. I replaced this with an equal sized shock from a rock crawler. Replaced the inner spring with the one from the kit to keep the spring constant the same.