Using a car tire on the rear wheel of a Yamaha xjr1300

Can anyone help with information on using a car tyre on a normal rear wheel of a solo ( used with a sidecar) I have been told , by two of the side car firms , that this should not be done. The wheels should be changed and the suspension. I do know that car tyres have been used on motor bike rims but after receiving this information it has me worried . I do know of some Goldwing riders who use car tires on the rear wheel and love them. They often get over 30000mls out of a tire on a Goldwing solo. Using a normal solo tire on a hack would make it very expensive indeed.

My idea would be to put a car tire on the rear and a rear tire , reversed, on the front. Similar to the trikes.

My last sidecar out fit was many years ago when motor bike tires weren't much different than car trended tires. Alas no longer made.