Need some advice on tires/wheels

[jgmick]

Started a project to build a 1/12 wheeled excavator (Gradall). Got the cab/boom/bucket part done, now looking at the chassis. Have most of that worked out but...

I am stuck on wheels/tires. Basically I don't know what I am doing. I have tried in the past to make solid tires out of molded urethane. That worked, sort of, but they don't work well in soft stuff. Plenty of traction, but no flotation. I think I need something with some give to it. I can get the appearance about right, they just don't function well.

Give me some advice on where to look for tires/rims and a general education on how they work and go together. Are they air inflated, thick rubber to get some load carrying capability, foam filled, other?

Dual tires on the back, what kind of hubs?

I'm not too concerned about exact scale, just something that looks about "right".

I plan on doing the drive train from scratch to suit me. Not (at least right now) trying to get too authentic on the rear axle/differential/transfer case. That may change as this thing evolves. (It's all easier when it is just on paper.)

All suggestions welcome, I'm plowing new ground here.