I need new rears for winter (they're just about bald) and somebody is selling used tires. Just for clarification 245/40/19's will fit where 255/35/19's are supposed to go right?

I was just going to buy new all seasons for the rear at about $200 a pop, but these are winters and will run me $200-300 … gotta haggle. They have 10/32's tread left.