Consider this recommendation
8/32” take away 4/32” equals ....not much tire for your money.
You do not replace tires at 4/32...Discount tire says that just so they can sell more tires....You replace the tire at 2/32 when you get to the wear bar. Thats why they have wear bars. At 2/32...the tires ability to remove water is diminished and thus the need for replacement. If you notice...dry weather tires (slicks) have no grooves because they don't need to remove water so there is no 32nds to go by...when its worn out there is a indicator that appears under the rubber to let you know time to replace. If you only drive in fry weather you could theoretically take a regular tire all the way down to 0/32 with no problems of tire failure. Get it wet and whoa boy.
SSREAPER
PS
still want to know what tire you have on your van with 16/32 of tread!