I have never tried it but most say the 195/55  is too wide for the swingarm and will rub, there have been a couple people that say it will fit but you may need  to move the inner flap on the front of the rear fender to keep it from rubbing. I think you drill a couple holes and wire tie it forward to the frame or something. the ones that I read that made it work say you have to put the tire in flat then air it up once in place. the % of trials that wouldn't fit was too high for me to risk trying it. I know that is a popular size for the 1800

if you get it to fit let us know and take pics if you can

I'm on my third car tire on the rear of my 1998 GL1500ct.  The first one was installed in Anchorage, AK and was a used P205 tire.  The second was a different brand P205 and rubbed some on the sidewalls until it wore down enough.  I had to watch the tire pressure pretty closely to keep it from rubbing too much.  Late last year I had a new P205 tire put on that was the same brand as the one installed in Anchorage.  It doesn't rub, but it does have to be installed while deflated and then inflated after it is in place.  I won't go so far as to say the Honda service department likes to install it.

I'm not at home to give the brand and all the size numbers from the tire.  I bought the tire from The Tire Rack and spooned the old tire off and the new one back onto the rim.  I had considered a P195 tire, but the 205 is almost identical in diameter to the original m/c tire.  My GPS confirms the speedometer indicated speed to be within 1-2 mph of the original m/c tire.