It doesn’t have to, with a 17” rim ~5.7” remains the maximum. With a 17x8” about 5.25” is a good amount, so with 17x7 keeping the wheel in the same spot would be more like 4.75”. I wouldn’t run less than 4.25”, but since you’re going to be limited to nothing wider than a 225 on that 17x7 even up to 4.25” of backspace would work.
