I have a Hollywood combined Bicycle and eTrike bicycle rack. This rack will fit 3 inch wheels. It is very sturdy and worked well for me. It has stabilizer straps and bars. (I included the second picture only as an example of current prices on these types of racks.)

I purchased it for $350 several years ago. It's in good shape and ready to go. These are hard to find at a reasonable price. I will consider a reasonable offer.