As other mentioned Kato sells only a single type of passenger car wheelsets. It is the 232040 set.
Dimensions:
Tread diameter: 0.216" (5.49mm) (or 34.5" in 1:1 scale - not quite 36")
Overall diameter: 0.274" (6.94mm)
Flange depth: 0.029" (0.74mm)
Wheel thickness: 0.073" (1.85mm)
Axle length: 0.563" (14.30mm)
Wheels are in gauge according to the NMRA gauge.
These are not the newer narrow tread/low flange passenger car wheels they use on some newer car sets. It would be nice if Kato did offer those newer wheelsets for sale because they look really good.