When you buy tires a store that advertises based on low prices, and you go in saying you want inexpensive tires, they sometimes will sell you a tire a size smaller to keep the price low. That happened to me, but I caught it the same day and returned them for the proper size tire- they didn’t charge more, but you have to pay attenion these days…as the other posters have said, no real problem, just keep the same size tires on the same axle.