275/60-15 is a 28" tall tire and is ideal on 8" wheels. You can used it on 7" wheels. The tire co. always say you need 7.5's but no one has a problem on a 7". On a 9C1 car in the rear you will find a 1/4" or up to 3/8" spacer between the wheel and hub will prevent tire rubbing on the frame. The 9C1 speedo is calibrated for a 28" tire (225/70-15) The spacer requires replacing the two rear hubs lugs with correspondingly longer studs. Cheap from Autozone and others, easy and widens your track 1/2 to 3/4" for a little handling uptick. Wide-Track flashback.