I tried to make a (can't be more) simple rover with the "old" fast wheels". I couldn't go faster than 9m/s on the runway, even though, the wheels a rated for 59m/s max speed.
I replaced the fast wheels by the new wheels, and manage to get to 39m/s veeeerrrrrrryyyy slowly.
Previously, I tried to redo a KSP 1 rover of mine with 2 structural sections, a probe core dans some wheels. It never managed to move an inch, except for gravity moving the rover on it's own.
The reaction wheels works well, though. So It think to buid a rover, we should set wheels around a reaction wheel and roll the whole rover