wheel weights for a 400 series tractor can be bought at a junk yard john deere used 16 inch rear wheels on there older combines they have a one piece wheel weight on the outside of the wheel it weights 160 pounds and there are also a two piece weight on the in side of the wheel you could use one or the other the in side weights can not be put on the inside of the case wheel because they will hit the wheel motor the two piece weights are around 100 pounds per tire the one piece are 160 per wheel they fit and can be found all over and cheap