Try looking at the Northern Tool Supply Catalog. They have a section on commercial handling equipment that had all kinds of wheels solid and air filled of all sizes and widths. Literally I think they had like 20-30 different wheels for everything from castors to hand trucks to stake bed trailers.
Colin & Bev Rainey KR2(td) N96TA Sanford, FL crain...@cfl.rr.com http://kr-builder.org/Colin/index.html