[TJean]

You want the birds to be able to get under the shaw, which is why the 24″ wheels. 20 ” is fine if you adjust the frame to give the birds the clearance.

Concerning the weight. The rim is not the issue but the actual tire. I use tires meant for wheelchairs that I get from a bike shop because I farm from a wheelchair. Cheap tires that puncture on sharp gravel will drive you crazy but so will heavy solid tire when you are hauling the thing up hill full of birds over rough terrain during mud season.

Mine is built on a collapsible bike trailer that I’ve pulled behind my wheelchair with groceries. It gives me a base I can refine my prototype upon as I figure out what works for me.

Also, consider just how far the birds can go from the top and your hawks et al, and size accordingly. Will you need more netting so they birds don’t hop the fence? How will you discourage the hawks from using the shaw as a fresh nuggets fly through? How are you going to stop the thing rolling down the hill or blowing over in the wind?

So if you use 20″ wheels, what else will you need to adapt to your conditions?