Did you consider 245 at all? I’ve seen that recommended for 8.5 19s
I wanted to get a size with the exact same outer tire diameter so the speedometer and odometer would not be off.
The closest you can get in a 245 tire is 245/50R18, which is 1.4% smaller. Resulting in the speedo/odo reading high by that same amount. Not a huge deal, but I wanted to be the same.
I'm also not sure about tire availability of 245/50R18 (or the 245/55R18 which is 2.1% larger). Some sizes are just really hard to find in the version of winter tire I wanted. The 255/50R18 is an exact match in size, but almost nobody made the tire in that size (and they were a lot more expensive). So the sweet-spot for me was 255/45R19.
255 tires fit very well on 8.5" rims. Even better than on the 9.5" rims that come stock.