When originally designed, the homologation rulebook mandated 16-inch wheels, so that's what the GT-R got. This limited the size of the brakes, and the four-piston calipers used by Nissan were not competitive. After the rules changed to allow 17-inch wheels, the GT-R V-spec (for Victory) emerged in February 1993 wearing 17" BBS mesh wheels (225/50/17) covering larger Brembo calipers. The clutch actuation changed from a push to a pull system and the car had a standard mechanical rear differential (the electronic rear differential did not show up until the R33 V-Spec). A year later, the V-Spec II appeared with a new sticker and wider tires (245/45 17).