I try to ask and make sure the tires I buy are within 1/4 inch of each other in circumference, most race tires are measured at the factory and the circumference is written on the sides of them so it is no big deal for the seller to give you a set like you want Take a look at your tires and see if there marked, I have had sets that are not what thier mark like when inflated I have also done the high pressure throw them in the sun trick, that doesn't always work if there is a large difference between the tires Yours should inflate to what you want