It would help if you told us what car it is, what type of wheels you have or what size the wheel studs are. But to give you some idea I have Mini-based cars with alloy wheels and 11/16" AF chromed steel nuts. I do the wheel nuts up to 42 lb-ft. I'm not sure what the thread size is but it's probably around 3/8" UNF. If you have steel wheels or alloys with steel inserts it's not too critical. When tightening steel nuts onto alloy be careful not to overtighten.