Ultra-Lite Folding Cart wheels have a 3" diameter. The base is 11" wide and 13 1/4" long.
Thanks for your question. To order spare parts, you will have to call the manufacturer directly. You can call Cosco Products on 1-800-544-1108 or contact them via their web page.
You will need to give them the item number of your hand truck which is 12301ABL1D.
Thank you for contacting us!