I am gathering materials for my first DIY tadpole, probably the AZ Warrior. I want to keep the down cost on my first project trike and I am trying to locate a source of 20 inch wheels with 14mm axles, with no success so far. Any suggestions? The only bike shop in my small town has nothing to sell, new or used, at this time. They are only doing repairs. I have never worked on bicycles beyond changing a tire or fixing a chain so I am totally ignorant as to how the hubs are designed and assembled. Can I use a rear wheel 20 inch without the sprocket assembly?