I got the tires at Harbor Freight and they work fine, they dont have grease points though. But a great deal at $9 a pop. We don't have princess auto out here, ive heard of it but never seen it. They are also 5/8 inch. I needed to save $ on those as I think I need to spend $60 on my drive wheels. (16" trailer tires) They work great though. The steering is actually very true! I am trying to really more or less mock up that stuff right now, when I get it moving and I know it will work I will go back and replace the paddle on the steering coloumn with an oval, get new threaded rod, and finish them off with those eye bearing doodads. I also have the engine on and a mocked up rear axle and rolled down the hill with it on idle, MAN DOES IT VIBRATE! LOL! Gonna need 2 work on that.