What is CG?
It sounds like you have a keyed axle.If it is you can remve the wheels.Northern hardwear has a large suplly of complete rimsDirt...all four tires are solid.
Happy days are here again!Happy wheel pulling.Dirt.....I believe you may have solved my problem. The "keyed axle" term is helpful. I actually found another thread referencing the same term. My axle looks identical, Hopefully, I'll be able to find a rim that fits a 3/4" keyed axle.