mmmm...I wouldn't say the Riken is rounder that others. At least mine isn't.
Some tires that advertise a rounder profile, such as the Cooper Zeon, have not performed very well according to those that have tried it.
I like the Riken. 23k miles without any issues.
Liquids, I'd be interested in why you rode darkside on your Valk but don't want to on your Roc. The Roc is at least the same or possibly a better candidate for darkside than the Valk, imho.
I just don't like the high speed handling of the car tires. It is not that they won't handle well at high speeds with the car tire. You just have to fight it a lot more. I did run a cooper zeon though on the Valk. Maybe I will try the Riken on the Rocket. It is a lot cheaper and I am about due for tires anyways.
After trying out different tire pressure and coming to find "the sweet spot", I have not had to fight road crown or hard turns. Car tire is great for me. As to which brand and tread, I think it is the riders choice. Just today I put 375 miles, 2 up, on my car tire and loved every bit of it. Highway ruts are the only time I have to fight the ride.
I just went dark 2 days ago I dont know if its me or not but I did not notice a whole lot of dif other than curves You just need to relearn a little but once your used to it its 2nd nature again. I did notice last nite in high winds that it did seem to lean alittle but it did that with the Metz also. I just look for the best spot in the lane and that usually takes care of the crown problem.
But so far totally satisfied with the change. My tire is the riken raptor
225 / 55 /16
I'm happy with my Raptor, and I run 28PSI.
Anymore and she handles like a wheel barrow,
or course, might have a lot to do with my roads here,
that, or the way I ride.....
Pick your tire by tread wear rating ( close to 300)the higher the number the harder the compound, tread pattern(small or no center rib, the larger the center rib the more it wants to follow the surface groves), speed, traction and temp ratings.
Start by going to tirerack.com. Look at the size (225/55/r16) is the closest for speedo, then read the above ratings. Thats how I chose mine.