I don't know what size brakes you guys have on B15's in the USA, but our N16's (same hub type) have few options for brakes, from 280mm down to 257mm. Not sure if that will be of any help to you though, but those smaller calipers will bolt up to a B15 hub (100mm bolt centre on the torque member vs 130mm on the ad22vf's). The rotor thickness is thinner than the ad22vf's though, around 22mm IIRC? will have to double check.