I'd love to run a car tire on my T, but I dunno. The guy in the link you posted was running a 195/55-16. I'm running a 180/70 now and I don't think there's room for a 15mm wider tire back there. Also, the diameter is 37.5mm smaller than a Valk-sized tire, which would lower the rear of the bike about 3/4" and make the engine even busier than it is now at speed.

You meet the nicest people on a Honda (forum).