I believe the Yokomo 32mm wheels are an offset wheel. Thats why they fit.
The rules have recently been changed to a maximum wheel and tyre size of 30mm. Yokomo was selling the 32mm tyres a long time before the change of rules.
Yokomo may develop a new 30mm wheel and tyre to suit the rules. But this doesn't help me because I cant get the Yokomo foams anyway.