OK, this is theoretical, not experience talking here, but this is what I would try.. I would take my heat gun (hair dryer if that is all you got) and heat up the rubber tire, have a dish of soap solution and a brush handy, and a coupe of big flat blade screwdrivers or something similar handy. start putting on the tire use the soap solution to lube it up good, and start prying it on with the screwdrivers. good luck
James K0UA